EDAC/altera: Skip defining unused structures for specific configs

The Altera EDAC driver has several features conditionally built
depending on Kconfig options. The edac_device_prv_data structures
are conditionally used in of_device_id tables. They reference other
functions and structures which can be defined as __maybe_unused.

Silence build warnings like:

  drivers/edac/altera_edac.c:643:37: warning:
      ‘altr_edac_device_inject_fops’ defined but not used [-Wunused-const-variable=]

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Link: https://lkml.kernel.org/r/20210601092704.203555-1-krzysztof.kozlowski@canonical.com

Author: krzk

drivers/edac/altera_edac.c

@@ -539,10 +539,18 @@ module_platform_driver(altr_edac_driver);
  * trigger testing are different for each memory.
  */
 
+#ifdef CONFIG_EDAC_ALTERA_OCRAM
 static const struct edac_device_prv_data ocramecc_data;
+#endif
+#ifdef CONFIG_EDAC_ALTERA_L2C
 static const struct edac_device_prv_data l2ecc_data;
+#endif
+#ifdef CONFIG_EDAC_ALTERA_OCRAM
 static const struct edac_device_prv_data a10_ocramecc_data;
+#endif
+#ifdef CONFIG_EDAC_ALTERA_L2C
 static const struct edac_device_prv_data a10_l2ecc_data;
+#endif
 
 static irqreturn_t altr_edac_device_handler(int irq, void *dev_id)
 {
@@ -569,9 +577,9 @@ static irqreturn_t altr_edac_device_handler(int irq, void *dev_id)
 	return ret_value;
 }
 
-static ssize_t altr_edac_device_trig(struct file *file,
-				     const char __user *user_buf,
-				     size_t count, loff_t *ppos)
+static ssize_t __maybe_unused
+altr_edac_device_trig(struct file *file, const char __user *user_buf,
+		      size_t count, loff_t *ppos)
 
 {
 	u32 *ptemp, i, error_mask;
@@ -640,27 +648,27 @@ static ssize_t altr_edac_device_trig(struct file *file,
 	return count;
 }
 
-static const struct file_operations altr_edac_device_inject_fops = {
+static const struct file_operations altr_edac_device_inject_fops __maybe_unused = {
 	.open = simple_open,
 	.write = altr_edac_device_trig,
 	.llseek = generic_file_llseek,
 };
 
-static ssize_t altr_edac_a10_device_trig(struct file *file,
-					 const char __user *user_buf,
-					 size_t count, loff_t *ppos);
+static ssize_t __maybe_unused
+altr_edac_a10_device_trig(struct file *file, const char __user *user_buf,
+			  size_t count, loff_t *ppos);
 
-static const struct file_operations altr_edac_a10_device_inject_fops = {
+static const struct file_operations altr_edac_a10_device_inject_fops __maybe_unused = {
 	.open = simple_open,
 	.write = altr_edac_a10_device_trig,
 	.llseek = generic_file_llseek,
 };
 
-static ssize_t altr_edac_a10_device_trig2(struct file *file,
-					  const char __user *user_buf,
-					  size_t count, loff_t *ppos);
+static ssize_t __maybe_unused
+altr_edac_a10_device_trig2(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos);
 
-static const struct file_operations altr_edac_a10_device_inject2_fops = {
+static const struct file_operations altr_edac_a10_device_inject2_fops __maybe_unused = {
 	.open = simple_open,
 	.write = altr_edac_a10_device_trig2,
 	.llseek = generic_file_llseek,
@@ -1697,9 +1705,9 @@ MODULE_DEVICE_TABLE(of, altr_edac_a10_device_of_match);
  * Based on xgene_edac.c peripheral code.
  */
 
-static ssize_t altr_edac_a10_device_trig(struct file *file,
-					 const char __user *user_buf,
-					 size_t count, loff_t *ppos)
+static ssize_t __maybe_unused
+altr_edac_a10_device_trig(struct file *file, const char __user *user_buf,
+			  size_t count, loff_t *ppos)
 {
 	struct edac_device_ctl_info *edac_dci = file->private_data;
 	struct altr_edac_device_dev *drvdata = edac_dci->pvt_info;
@@ -1729,9 +1737,9 @@ static ssize_t altr_edac_a10_device_trig(struct file *file,
  * slightly. A few Arria10 peripherals can use this injection function.
  * Inject the error into the memory and then readback to trigger the IRQ.
  */
-static ssize_t altr_edac_a10_device_trig2(struct file *file,
-					  const char __user *user_buf,
-					  size_t count, loff_t *ppos)
+static ssize_t __maybe_unused
+altr_edac_a10_device_trig2(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos)
 {
 	struct edac_device_ctl_info *edac_dci = file->private_data;
 	struct altr_edac_device_dev *drvdata = edac_dci->pvt_info;