drm/i915: Don't set undefined bits in dirty_pipes

skl_commit_modeset_enables() straight up compares dirty_pipes
with a bitmask of already committed pipes. If we set bits in
dirty_pipes for non-existent pipes that comparison will never
work right. So let's limit ourselves to bits that exist.

And we'll do the same for the active_pipes_changed bitmask.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191011200949.7839-5-ville.syrjala@linux.intel.comReviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -5360,7 +5360,7 @@ skl_ddb_add_affected_pipes(struct intel_atomic_state *state)
 		if (ret)
 			return ret;
 
-		state->active_pipe_changes = ~0;
+		state->active_pipe_changes = INTEL_INFO(dev_priv)->pipe_mask;
 
 		/*
 		 * We usually only initialize state->active_pipes if we
@@ -5386,7 +5386,7 @@ skl_ddb_add_affected_pipes(struct intel_atomic_state *state)
 	 * to grab the lock on *all* CRTC's.
 	 */
 	if (state->active_pipe_changes || state->modeset) {
-		state->wm_results.dirty_pipes = ~0;
+		state->wm_results.dirty_pipes = INTEL_INFO(dev_priv)->pipe_mask;
 
 		ret = intel_add_all_pipes(state);
 		if (ret)