media: ov2685: mark PM functions as __maybe_unused

Without CONFIG_PM, we get a harmless build warning:

drivers/media/i2c/ov2685.c:516:12: error: 'ov2685_runtime_suspend' defined but not used [-Werror=unused-function]
static int ov2685_runtime_suspend(struct device *dev)
^~~~~~~~~~~~~~~~~~~~~~
drivers/media/i2c/ov2685.c:507:12: error: 'ov2685_runtime_resume' defined but not used [-Werror=unused-function]
static int ov2685_runtime_resume(struct device *dev)

This marks the affected functions as __maybe_unused.

Fixes: e3861d9118c8 ("media: ov2685: add support for OV2685 sensor")

Signed-off-by: Arnd Bergmann <[e-mail]>
[[e-mail]: fixed typo in Subject: was ov5695]
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/i2c/ov2685.c

···
 }
 #endif
 
-static int ov2685_runtime_resume(struct device *dev)
+static int __maybe_unused ov2685_runtime_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);
···
 	return __ov2685_power_on(ov2685);
 }
 
-static int ov2685_runtime_suspend(struct device *dev)
+static int __maybe_unused ov2685_runtime_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct v4l2_subdev *sd = i2c_get_clientdata(client);