PM: Make suspend_device() static

suspend_device() can become static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/base/power/main.c

@@ -415,7 +415,7 @@ EXPORT_SYMBOL_GPL(device_power_down);
  *	@dev:	Device.
  *	@state:	Power state device is entering.
  */
-int suspend_device(struct device *dev, pm_message_t state)
+static int suspend_device(struct device *dev, pm_message_t state)
 {
 	int error = 0;