kmssink: refine resize logic

Refine scale check to get scale ratio by trying setplane from large
scale to small. When show frame, check if the required ratio in range,
if not, try not scale, if video is totally out of display, use the last
render area.

upstream status: i.Mx specific

Conflicts:
	sys/kms/gstkmssink.c
	sys/kms/gstkmssink.h
2 files changed