smem: Allow usage of RGBA

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
(cherry picked from commit 1eb0e68191ef5187b4b15896a64b3b8db3ea7b9a)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/stream_out/smem.c

@@ -230,6 +230,7 @@ static sout_stream_id_t *AddVideo( sout_stream_t *p_stream, es_format_t *p_fmt )
     switch( p_fmt->i_codec )
     {
         case VLC_CODEC_RGB32:
+        case VLC_CODEC_RGBA:
             i_bits_per_pixel = 32;
             break;
         case VLC_CODEC_I444: