usb: dwc3: 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 SET_SYSTEM_SLEEP_PM_OPS are only used
when the CONFIG_PM_SLEEP is enabled. Unnecessary CONFIG_PM ifdefs
are removed.

drivers/usb/dwc3/core.c:682:12: warning: 'dwc3_suspend' defined but not used [-Wunused-function]
drivers/usb/dwc3/core.c:709:12: warning: 'dwc3_resume' defined but not used [-Wunused-function]
drivers/usb/dwc3/dwc3-omap.c:430:12: warning: 'dwc3_omap_suspend' defined but not used [-Wunused-function]
drivers/usb/dwc3/dwc3-omap.c:440:12: warning: 'dwc3_omap_resume' defined but not used [-Wunused-function]
drivers/usb/dwc3/dwc3-exynos.c:185:12: warning: 'dwc3_exynos_suspend' defined but not used [-Wunused-function]
drivers/usb/dwc3/dwc3-exynos.c:194:12: warning: 'dwc3_exynos_resume' defined but not used [-Wunused-function]

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c
index 1ea7bd8..a8afe6e 100644
--- a/drivers/usb/dwc3/dwc3-exynos.c
+++ b/drivers/usb/dwc3/dwc3-exynos.c
@@ -181,7 +181,7 @@
 MODULE_DEVICE_TABLE(of, exynos_dwc3_match);
 #endif
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int dwc3_exynos_suspend(struct device *dev)
 {
 	struct dwc3_exynos *exynos = dev_get_drvdata(dev);
@@ -212,7 +212,7 @@
 #define DEV_PM_OPS	(&dwc3_exynos_dev_pm_ops)
 #else
 #define DEV_PM_OPS	NULL
-#endif /* CONFIG_PM */
+#endif /* CONFIG_PM_SLEEP */
 
 static struct platform_driver dwc3_exynos_driver = {
 	.probe		= dwc3_exynos_probe,