ALSA: control - double free in snd_ctl_led_init()

"group - 1" was intended here instead of "group".  The current error
handling will double free the first item in the array and leak the last
item.

Fixes: cb17fe00

 ("ALSA: control - add sysfs support to the LED trigger module")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/YHBJ4frGxErWB182@mwanda
Signed-off-by: Takashi Iwai <tiwai@suse.de>