drm/i915: Only wait for required lanes in vlv_wait_port_ready()

Currently vlv_wait_port_ready() waits for all four lanes on the
appropriate channel. This no longer works on CHV when the unused
lanes may be power gated. So pass in a mask of lanes that the
caller is expecting to be ready.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by:  Deepak S<deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 930ea69..ea3368e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1013,7 +1013,8 @@
 }
 int ironlake_get_lanes_required(int target_clock, int link_bw, int bpp);
 void vlv_wait_port_ready(struct drm_i915_private *dev_priv,
-			 struct intel_digital_port *dport);
+			 struct intel_digital_port *dport,
+			 unsigned int expected_mask);
 bool intel_get_load_detect_pipe(struct drm_connector *connector,
 				struct drm_display_mode *mode,
 				struct intel_load_detect_pipe *old,