Instead of keying off vblank for psr, just flush every time
we get an atomic update. This ensures that cursor updates
will properly disable psr (without turning vblank on/off),
and unifies the paths between fb_dirty and atomic psr
enable/disable.
Reviewed-by: Yakir Yang <ykk@rock-chips.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>