[ALSA] [SPARSE] Use NULL instead of 0

HDA Codec driver
Use NULL for pointers instead of 0.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_realtek.c

@@ -1050,7 +1050,7 @@ static int patch_alc880(struct hda_codec *codec)
  * never used.
  */
 static struct alc_channel_mode alc260_modes[1] = {
-	{ 2, 0 },
+	{ 2, NULL },
 };
 
 snd_kcontrol_new_t alc260_base_mixer[] = {