Merge branch 'mediatek-drm-fixes-5.2' of https://github.com/ckhu-mediatek/linux.git-tags into drm-fixes

CK writes:

This include unbind error fix, clock control flow refinement, and PRIME
mmap with page offset.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1560325868.3259.6.camel@mtksdaap41