platform/x86: amd-pmc: Fix CONFIG_DEBUG_FS check

lkp reported that CONFIG_DEBUG_FS was not defined because of wrong usage
if macro, correcting it now.

Fixes: 156ec47 ("platform/x86: amd-pmc: Add AMD platform support for S2Idle")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20201230081028.2615217-1-Shyam-sundar.S-k@amd.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/amd-pmc.c

@@ -85,7 +85,7 @@ static inline void amd_pmc_reg_write(struct amd_pmc_dev *dev, int reg_offset, u3
 	iowrite32(val, dev->regbase + reg_offset);
 }
 
-#if CONFIG_DEBUG_FS
+#ifdef CONFIG_DEBUG_FS
 static int smu_fw_info_show(struct seq_file *s, void *unused)
 {
 	struct amd_pmc_dev *dev = s->private;