Change RGB2 to RGB8

Signed-off-by: Rémi Duraffort <ivoire@videolan.org>
(cherry picked from commit 098df76ff5ea0cd087a36ec67021607de2e3a49c)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

include/vlc_fourcc.h

@@ -147,7 +147,7 @@
 /* Palettized RGB with palette element R:G:B */
 #define VLC_CODEC_RGBP      VLC_FOURCC('R','G','B','P')
 /* 8 bits RGB */
-#define VLC_CODEC_RGB8      VLC_FOURCC('R','G','B','2')
+#define VLC_CODEC_RGB8      VLC_FOURCC('R','G','B','8')
 /* 15 bits RGB stored on 16 bits */
 #define VLC_CODEC_RGB15     VLC_FOURCC('R','V','1','5')
 /* 16 bits RGB store on a 16 bits */