[ALSA] ali5451 - Don't build non-existing modem PCM

ALI5451 driver
Don't build the modem PCM if the corresponding codec isn't detected.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ali5451/ali5451.c

@@ -1994,6 +1994,8 @@ static int __devinit snd_ali_mixer(ali_t * codec)
 			snd_printk("ali mixer %d creating error.\n", i);
 			if(i == 0)
 				return err;
+			codec->num_of_codecs = 1;
+			break;
 		}
 	}