drm/radeon/kms: switch to condition waiting for reclocking

We tried to implement interruptible waiting with timeout (it was broken
anyway) which was not a good idea as explained by Andrew. It's possible
to avoid using additional variable but actually it inroduces using more
complex in-kernel tools. So simply add one variable for condition.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index c522901..5b56a1b 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2765,6 +2765,7 @@
 			case 0: /* D1 vblank */
 				if (disp_int & LB_D1_VBLANK_INTERRUPT) {
 					drm_handle_vblank(rdev->ddev, 0);
+					rdev->pm.vblank_sync = true;
 					wake_up(&rdev->irq.vblank_queue);
 					disp_int &= ~LB_D1_VBLANK_INTERRUPT;
 					DRM_DEBUG("IH: D1 vblank\n");
@@ -2786,6 +2787,7 @@
 			case 0: /* D2 vblank */
 				if (disp_int & LB_D2_VBLANK_INTERRUPT) {
 					drm_handle_vblank(rdev->ddev, 1);
+					rdev->pm.vblank_sync = true;
 					wake_up(&rdev->irq.vblank_queue);
 					disp_int &= ~LB_D2_VBLANK_INTERRUPT;
 					DRM_DEBUG("IH: D2 vblank\n");