ALSA: sound/pci/hda: fix sparse warning: different signedness

Fix this sparse warning:
  sound/pci/hda/hda_codec.c:1544:19: warning: incorrect type in assignment (different signedness)
  sound/pci/hda/hda_codec.c:1544:19:    expected unsigned long *vals
  sound/pci/hda/hda_codec.c:1544:19:    got long *<noident>

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>