[ALSA] Big kfree NULL check cleanup - sound

Modules: AD1889 driver,RME9652 driver

This is the sound/ part of the big kfree cleanup patch.

Remove pointless checks for NULL prior to calling kfree() in sound/.

Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>