media: intel-ipu3: cio2: mark PM functions as __maybe_unused

When CONFIG_PM is disabled, we get harmless warnings about the
suspend/resume callbacks being unused:

drivers/media/pci/intel/ipu3/ipu3-cio2.c:1993:12: error: 'cio2_resume' defined but not used [-Werror=unused-function]
drivers/media/pci/intel/ipu3/ipu3-cio2.c:1967:12: error: 'cio2_suspend' defined but not used [-Werror=unused-function]

This marks them as __maybe_unused to shut up the warnings.

Fixes: c2a6a07a ("media: intel-ipu3: cio2: add new MIPI-CSI2 driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/pci/intel/ipu3/ipu3-cio2.c

@@ -1961,7 +1961,7 @@ static void cio2_fbpt_rearrange(struct cio2_device *cio2, struct cio2_queue *q)
 		cio2_fbpt_entry_enable(cio2, q->fbpt + i * CIO2_MAX_LOPS);
 }
 
-static int cio2_suspend(struct device *dev)
+static int __maybe_unused cio2_suspend(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct cio2_device *cio2 = pci_get_drvdata(pci_dev);
@@ -1987,7 +1987,7 @@ static int cio2_suspend(struct device *dev)
 	return 0;
 }
 
-static int cio2_resume(struct device *dev)
+static int __maybe_unused cio2_resume(struct device *dev)
 {
 	struct pci_dev *pci_dev = to_pci_dev(dev);
 	struct cio2_device *cio2 = pci_get_drvdata(pci_dev);