Support decoding unaligned rgb24 lagarith.

Fixes ticket #1214.

libavcodec/lagarith.c

@@ -506,7 +506,8 @@ static int lag_decode_frame(AVCodecContext *avctx,
         offset_ry += 4;
         offs[3] = AV_RL32(buf + 9);
     case FRAME_ARITH_RGB24:
-        if (frametype == FRAME_ARITH_RGB24)
+    case FRAME_U_RGB24:
+        if (frametype == FRAME_ARITH_RGB24 || frametype == FRAME_U_RGB24)
             avctx->pix_fmt = PIX_FMT_RGB24;
 
         if (avctx->get_buffer(avctx, p) < 0) {