Add 'tsc2' as fourcc alias for VLC_CODEC_TSC2 / TechSmith Screen Codec

2.

This fixed playback of TSC2 samples on
http://streams.videolan.org/misc/tsc2/ .

src/misc/fourcc.c

@@ -939,6 +939,7 @@ static const entry_t p_list_video[] = {
 
     B(VLC_CODEC_TSC2, "TechSmith Screen Codec 2"),
         A("MSA1"),
+        A("tsc2"),
 
     B(VLC_CODEC_MTS2, "Microsoft Expression Encoder Screen"),
         A("MTS2"),