h264dec: only fill referenced dpb pictures for vaapi
h264dec: only fill referenced dpb pictures for vaapi

Only fill the VAAPI picture reference list with pictures
that are currently referenced in the dpb.  Loading
unreferenced dpb pictures in VAAPI is unnecessary.

Signed-off-by: U. Artie Eoff <32aece0d55055227b44d04b7d0051cf3d04ee871@intel.com>

seanvk/libyami,dspmeng/libyami,lizhong1008/libyami,YuJiankang/libyami,dspmeng/libyami,yizhouwei/libyami,zhaobob/libyami,lizhong1008/libyami,dspmeng/libyami,stripes416/libyami,stripes416/libyami,seanvk/libyami,uartie/libyami,yizhouwei/libyami,YuJiankang/libyami,zhaobob/libyami,01org/libyami,yizhouwei/libyami,01org/libyami,01org/libyami,lizhong1008/libyami,stripes416/libyami,uartie/libyami,zhaobob/libyami,uartie/libyami,seanvk/libyami,YuJiankang/libyami