ALSA: fix possible memory leak in snd_mixer_oss_build_input()

uinfo has been allocated in this function and should be
freed before leaving from the error handling cases.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/oss/mixer_oss.c

@@ -1046,6 +1046,7 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer, struct snd_mix
 			
 		if (kctl->info(kctl, uinfo)) {
 			up_read(&mixer->card->controls_rwsem);
+			kfree(uinfo);
 			return 0;
 		}
 		strcpy(str, ptr->name);
@@ -1061,6 +1062,7 @@ static int snd_mixer_oss_build_input(struct snd_mixer_oss *mixer, struct snd_mix
 				uinfo->value.enumerated.item = slot.capture_item;
 				if (kctl->info(kctl, uinfo)) {
 					up_read(&mixer->card->controls_rwsem);
+					kfree(uinfo);
 					return 0;
 				}
 				if (!strcmp(uinfo->value.enumerated.name, str)) {