[PATCH] alsa: fix error paths in snd_ctl_elem_add()

Fix bugs in error paths of snd_ctl_elem_add()
 - NULL reference
 - double free (already freed in snd_ctl_add())

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>