rtc: fix platform driver hotplug/coldplug

Since 43cc71eed1250755986da4c0f9898f9a635cb3bf, the platform modalias is
prefixed with "platform:".  Add MODULE_ALIAS() to the hotpluggable RTC
platform drivers, to re-enable module auto loading.

[dbrownell@users.sourceforge.net: more drivers, minor fix]
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <greg@kroah.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 33795e5..52abffc8 100644
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -407,3 +407,4 @@
 MODULE_AUTHOR("Rick Bronson");
 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:at91_rtc");