media/gpu/v4l2: remove unneeded statement

V4L2Request::ApplyCtrls(), which is called on the next line, will do
this for us.

BUG=None
TEST=video.DecodeAccel.h264 passes on Kukui.

Change-Id: I34196a4d65c03a0bec7da87854d226b8905b3027
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2421992
Commit-Queue: Fritz Koenig <frkoenig@chromium.org>
Reviewed-by: Fritz Koenig <frkoenig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809409}

media/gpu/v4l2/v4l2_decode_surface.cc

@@ -140,7 +140,6 @@ void V4L2RequestDecodeSurface::PrepareSetCtrls(
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   DCHECK_NE(ctrls, nullptr);
 
-  ctrls->which = V4L2_CTRL_WHICH_REQUEST_VAL;
   request_ref_.ApplyCtrls(ctrls);
 }