ALSA: cmipci: Allocate with GFP_KERNEL instead of GFP_ATOMIC

save_mixer_state() is called in a sleepable context, so it's safe to
allocate with GFP_KERNEL instead of the current GFP_ATOMIC.  The
GFP_ATOMIC usage must have been based on an incorrect assumption in
the very old code base.

Signed-off-by: Takashi Iwai <tiwai@suse.de>