Merge branch 'mediatek-drm-fixes-4.20' of https://github.com/ckhu-mediatek/linux.git-tags into drm-fixes

Single bridge attachment fix.

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1544407975.18825.3.camel@mtksdaap41