ENGR00255491 ov5640: Fix build break by make modules

Fix the kernel modules building error for mx6q/mx6dl as follows:

LD [M] drivers/usb/gadget/g_serial.o
Building modules, stage 2.
MODPOST 48 modules
ERROR: "csi_enable_mclk" [drivers/media/video/mxc/capture/ov5640_camera.ko]
			undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2

Signed-off-by: Robby Cai <R63905@freescale.com>

drivers/media/video/mxc/capture/ov5640.c

@@ -1823,8 +1823,9 @@ static int ov5640_probe(struct i2c_client *client,
 	if (plat_data->pwdn)
 		plat_data->pwdn(0);
 
-	if (cpu_is_mx6sl())
-		csi_enable_mclk(CSI_MCLK_I2C, true, true);
+#ifdef CONFIG_SOC_IMX6SL
+	csi_enable_mclk(CSI_MCLK_I2C, true, true);
+#endif
 	retval = ov5640_read_reg(OV5640_CHIP_ID_HIGH_BYTE, &chip_id_high);
 	if (retval < 0 || chip_id_high != 0x56) {
 		pr_warning("camera ov5640 is not found\n");
@@ -1841,8 +1842,9 @@ static int ov5640_probe(struct i2c_client *client,
 	if (plat_data->pwdn)
 		plat_data->pwdn(1);
 
-	if (cpu_is_mx6sl())
-		csi_enable_mclk(CSI_MCLK_I2C, false, false);
+#ifdef CONFIG_SOC_IMX6SL
+	csi_enable_mclk(CSI_MCLK_I2C, false, false);
+#endif
 
 	camera_plat = plat_data;