Add VP8 decoding API

Added new profile, buffer types and data structures for VP8 decoding

Signed-off-by: Jonathan Bian <jonathan.bian@intel.com>
[Fixed conflicts and remove unused profiles]
Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>
Added VASliceParameterBufferVP8 to describe data partition related fields.
Changes to VASliceParameterBufferVP8 to make it consistent with slice parameter buffer structure for other formats.
libva: change the types of all fields in VABoolCoderContextVPX

BZ: 120268

Change the types of all fields in VABoolCoderContextVPX to
"unsigned char" to avoid potential bugs.

Change-Id: I483f115080cefe45ae49503ff5737c7dfff305a8
Signed-off-by: Tianmi Chen <tianmi.chen@intel.com>
vp8 dec: refine va_dec_vp8.h

add clear notation for: key_frame/VABoolCoderContextVPX.count/num_of_partitions/partition_size[0]
remove mb_skip_coeff since it can be deduced from mb_no_coeff_skip if it is required

Signed-off-by: Zhao, Halley <halley.zhao@intel.com>
vp8 dec: add clear notation for qindex

Signed-off-by: Zhong Li <zhong.li@intel.com>