g3dvl: Define PIPE_VIDEO_CODEC_UNKNOWN for failures.

gcc 4.4 seems particularly picky with int -> enum conversions.

src/gallium/include/pipe/p_defines.h

@@ -318,6 +318,7 @@ enum pipe_transfer_usage {
 
 enum pipe_video_codec
 {
+   PIPE_VIDEO_CODEC_UNKNOWN = 0,
    PIPE_VIDEO_CODEC_MPEG12,   /**< MPEG1, MPEG2 */
    PIPE_VIDEO_CODEC_MPEG4,    /**< DIVX, XVID */
    PIPE_VIDEO_CODEC_VC1,      /**< WMV */

src/gallium/include/pipe/p_video_state.h

@@ -63,10 +63,9 @@ u_reduce_video_profile(enum pipe_video_profile profile)
          return PIPE_VIDEO_CODEC_MPEG4_AVC;
 
       default:
-         assert(false);
+         assert(0);
+         return PIPE_VIDEO_CODEC_UNKNOWN;
    }
-
-   return -1;
 }
 
 enum pipe_mpeg12_picture_type