Fix wrong selection of VP8 video decoder on some Samsung devices.

- Create HW decoder using first codec in MediaCoedcList instead of
using createDecoderByType function. Later may result in opening
OMX.SEC.vp8.dec decoder, which can not be used for surface decoding.
- Revert r279297 and mark all OMX.SEC.* codecs as non HW accelerated.

BUG=408353, 396578
R=qinmin@chromium.org

Review URL: https://codereview.chromium.org/605883002

Cr-Commit-Position: refs/heads/master@{#297667}