drm/exynos: fixed overlay updating time at page flip.

buffer addess is set to shadow register and then applied to
real register at vsync front porch time.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
3 files changed