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/core/driver.c b/drivers/usb/core/driver.c
index 9bffd26..874dec3 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1493,10 +1493,6 @@
 	return status;
 }
 
-#endif /* CONFIG_PM */
-
-#ifdef CONFIG_PM_RUNTIME
-
 /**
  * usb_enable_autosuspend - allow a USB device to be autosuspended
  * @udev: the USB device which may be autosuspended
@@ -1876,7 +1872,7 @@
 	return ret;
 }
 
-#endif /* CONFIG_PM_RUNTIME */
+#endif /* CONFIG_PM */
 
 struct bus_type usb_bus_type = {
 	.name =		"usb",