lavc/v4l2_context: fix compile warning for incompatible pointer type

Signed-off-by: Linjie Fu <linjie.fu@intel.com>
Reviewed-by: Andriy Gelman <andriy.gelman@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/v4l2_context.c

@@ -48,7 +48,7 @@ static inline V4L2m2mContext *ctx_to_m2mctx(V4L2Context *ctx)
         container_of(ctx, V4L2m2mContext, capture);
 }
 
-static inline AVClass *logger(V4L2Context *ctx)
+static inline AVCodecContext *logger(V4L2Context *ctx)
 {
     return ctx_to_m2mctx(ctx)->avctx;
 }