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-m48t59.c b/drivers/rtc/rtc-m48t59.c
index cd0bbc0..013e6c1 100644
--- a/drivers/rtc/rtc-m48t59.c
+++ b/drivers/rtc/rtc-m48t59.c
@@ -465,6 +465,9 @@
 	return 0;
 }
 
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:rtc-m48t59");
+
 static struct platform_driver m48t59_rtc_driver = {
 	.driver		= {
 		.name	= "rtc-m48t59",