removing typecasts for pcm_mixer cause more issues than before

slstatus.c

@@ -514,8 +514,8 @@ vol_perc(const char *soundcard)
 	pcm_mixer = snd_mixer_find_selem(handle, vol_info);
 	mas_mixer = snd_mixer_find_selem(handle, mute_info);
 
-	snd_mixer_selem_get_playback_volume_range(pcm_mixer, &min, &max);
-	snd_mixer_selem_get_playback_volume(pcm_mixer, SND_MIXER_SCHN_MONO, &vol);
+	snd_mixer_selem_get_playback_volume_range((snd_mixer_elem_t *)pcm_mixer, &min, &max);
+	snd_mixer_selem_get_playback_volume((snd_mixer_elem_t *)pcm_mixer, SND_MIXER_SCHN_MONO, &vol);
 	snd_mixer_selem_get_playback_switch(mas_mixer, SND_MIXER_SCHN_MONO, &mute);
 
 	if (vol_info)