drm/i915/mst: Clear ACT just before triggering payload allocation

Follow the bspec sequence more closely and clear ACT sent just
before triggering the allocation. Can't see why we'd want to
deviate from the spec sequence here.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231018154123.5479-4-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/intel_dp_mst.c

@@ -791,8 +791,6 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
 
 	drm_WARN_ON(&dev_priv->drm, pipe_config->has_pch_encoder);
 
-	clear_act_sent(encoder, pipe_config);
-
 	if (intel_dp_is_uhbr(pipe_config)) {
 		const struct drm_display_mode *adjusted_mode =
 			&pipe_config->hw.adjusted_mode;
@@ -806,6 +804,8 @@ static void intel_mst_enable_dp(struct intel_atomic_state *state,
 
 	intel_ddi_enable_transcoder_func(encoder, pipe_config);
 
+	clear_act_sent(encoder, pipe_config);
+
 	intel_de_rmw(dev_priv, TRANS_DDI_FUNC_CTL(trans), 0,
 		     TRANS_DDI_DP_VC_PAYLOAD_ALLOC);