drm/i915/ddi: Add missing wait-for-active for HDMI aligning with bspec updates

After enabling DDI_BUF_CTL, wait for DDI_BUF_CTL to be active.
Bspec:4232,53339,49191,54145
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221127052232.3942831-3-ankit.k.nautiyal@intel.com

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

@@ -2946,6 +2946,8 @@ static void intel_enable_ddi_hdmi(struct intel_atomic_state *state,
 	}
 	intel_de_write(dev_priv, DDI_BUF_CTL(port), buf_ctl);
 
+	intel_wait_ddi_buf_active(dev_priv, port);
+
 	intel_audio_codec_enable(encoder, crtc_state, conn_state);
 }