Fix the bug which made VP8 denoiser not bit-exact between C code and SSE code.

This issue is found when the denoising mode is set to kDenoiserOnYUVAggressive.
Updated the C code to make it the same with SSE version.

I also changed several lines in VP9 denoiser for the code style.

Change-Id: I640d48cf946fe8c6a400e6e252107501d1e226d3
3 files changed