libs: encoder: Consider vp9 profiles based on input format.
libs: encoder: Consider vp9 profiles based on input format.

Only support GST_VAAPI_PROFILE_VP9_0 and GST_VAAPI_PROFILE_VP9_2 now.

Fix: #184

ceyusa/gstreamer-vaapi,GStreamer/gstreamer-vaapi,GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi