avcodec: v4l2_context: remove unnecessary code

Fixes CID 1418358

Signed-off-by: Jorge Ramirez-Ortiz <jramirez@baylibre.com>

libavcodec/v4l2_context.c

@@ -446,9 +446,7 @@ static int v4l2_get_raw_format(V4L2Context* ctx, enum AVPixelFormat *p)
 
     if (pixfmt != AV_PIX_FMT_NONE) {
         ret = v4l2_try_raw_format(ctx, pixfmt);
-        if (ret)
+        if (!ret)
-            pixfmt = AV_PIX_FMT_NONE;
-        else
             return 0;
     }