[PATCH] rtc: remove superfluous call to call to cdev_del()

If cdev_add() fails there is no good reason to call cdev_del().

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>