[PATCH] RTC: handle sysfs errors

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>