mtd: r852: add CONFIG_PM_SLEEP to suspend/resume functions

Add CONFIG_PM_SLEEP to suspend/resume functions to fix the following
build warning when CONFIG_PM_SLEEP is not selected. This is because
sleep PM callbacks defined by SIMPLE_DEV_PM_OPS are only used when
the CONFIG_PM_SLEEP is enabled. Also, unnecessary NULL defines are
removed.

drivers/mtd/nand/r852.c:1006:12: warning: 'r852_suspend' defined but not used [-Wunused-function]
drivers/mtd/nand/r852.c:1027:12: warning: 'r852_resume' defined but not used [-Wunused-function]

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/r852.c

@@ -1002,7 +1002,7 @@ void r852_shutdown(struct pci_dev *pci_dev)
 	pci_disable_device(pci_dev);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int r852_suspend(struct device *device)
 {
 	struct r852_device *dev = pci_get_drvdata(to_pci_dev(device));
@@ -1055,9 +1055,6 @@ static int r852_resume(struct device *device)
 	r852_update_card_detect(dev);
 	return 0;
 }
-#else
-#define r852_suspend	NULL
-#define r852_resume	NULL
 #endif
 
 static const struct pci_device_id r852_pci_id_tbl[] = {