USB / PM: Drop CONFIG_PM_RUNTIME from the USB core

After commit b2b49ccbdd54 (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is
selected) PM_RUNTIME is always set if PM is set, so quite a few
depend on CONFIG_PM (or even dropped in some cases).

Replace CONFIG_PM_RUNTIME with CONFIG_PM in the USB core code
and documentation.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/phy/phy-msm-usb.c b/drivers/usb/phy/phy-msm-usb.c
index 7843ef7..29be0e6 100644
--- a/drivers/usb/phy/phy-msm-usb.c
+++ b/drivers/usb/phy/phy-msm-usb.c
@@ -1761,7 +1761,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_PM_RUNTIME
+#ifdef CONFIG_PM
 static int msm_otg_runtime_idle(struct device *dev)
 {
 	struct msm_otg *motg = dev_get_drvdata(dev);