msdk: enc: fix missing some frames to be encoded

There was not handling the end of encoding sequence in encoder.
This patch does drain any remaining internal streams while decoder
already does this.

Document says:
"To mark the end of the encoding sequence, call this function with a
NULL surface
pointer. Repeat the call to drain any remaining internally cached
frame at a time—until MFX_ERR_MORE_DATA is returned."
2 files changed