drm/rockchip: Suspend DP late

In commit fe64ba5c ("drm/rockchip: Resume DP early") we moved
resume to be early but left suspend at its normal time.  This seems
like it could be OK, but casues problems if a suspend gets interrupted
partway through.  The OS only balances matching suspend/resume levels.
...so if suspend was called then resume will be called.  If suspend
late was called then resume early will be called.  ...but if suspend
was called resume early might not get called.  This leads to an
unbalance in the clock enables / disables.

Lets take the simple fix and just move suspend to be late to match.
This makes the PM core take proper care in keeping things balanced.

Fixes: fe64ba5c ("drm/rockchip: Resume DP early")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190802184616.44822-1-dianders@chromium.org

drivers/gpu/drm/rockchip/analogix_dp-rockchip.c

@@ -432,7 +432,7 @@ static int rockchip_dp_resume(struct device *dev)
 
 static const struct dev_pm_ops rockchip_dp_pm_ops = {
 #ifdef CONFIG_PM_SLEEP
-	.suspend = rockchip_dp_suspend,
+	.suspend_late = rockchip_dp_suspend,
 	.resume_early = rockchip_dp_resume,
 #endif
 };