[Encode] Fixed VP9 444 frame header

According VP9 spec section 7.2.2 color config semantics,
both subsampling_x and subsampling_y should be 0 for YUV444.
Only YUV440 subsampling_x=0 and subsampling_y=1.

fixes #1074

Signed-off-by: Lim Siew Hoon <siew.hoon.lim@intel.com>
1 file changed