radeonsi/vcn: Add ability to encode with ltr
Adds the ability to encode frames using ltr.
- reads
flags
field fromCurrPic
struct in pps for VA_PICTURE_H264_LONG_TERM_REFERENCE. If found,Curr_pic.frame_idx
wil be used for the long term reference index - In
get_picture_storage
, check if current frame is ltr, and whether its ref frame is ltr. - In
radeon_enc_slice_header
, adds theref_pic_list_modification_flag_l0
andlong_term_reference_flag
for ltr