drm/atomic: Update legacy DPMS state during modesets, v3.

This is required for DPMS to work correctly, during a modeset
the DPMS property should be turned off, unless the state is
crtc is made active in which case it should be set to DPMS on.

Changes since v1:
- Set DPMS to off when a connector is removed from a crtc too.
- Update the legacy dpms property too.
- Add an exception for the legacy dpms paths, it updates its own state.
Changes since v2:
- Do not preserve dpms property.

Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 13a6608..43b0f17 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12349,16 +12349,9 @@
 			continue;
 
 		if (crtc->state->active) {
-			struct drm_property *dpms_property =
-				dev->mode_config.dpms_property;
-
-			connector->dpms = DRM_MODE_DPMS_ON;
-			drm_object_property_set_value(&connector->base, dpms_property, DRM_MODE_DPMS_ON);
-
 			intel_encoder = to_intel_encoder(connector->encoder);
 			intel_encoder->connectors_active = true;
-		} else
-			connector->dpms = DRM_MODE_DPMS_OFF;
+		}
 	}
 }