watchdog: orion_wdt: Add platform alias

...so that it's automatically picked up on relevant platforms.
Tested on Kirkwood-based GuruPlug.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.c
index 7c18b3b..87ed2b9 100644
--- a/drivers/watchdog/orion_wdt.c
+++ b/drivers/watchdog/orion_wdt.c
@@ -225,4 +225,5 @@
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:orion_wdt");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);