drm/i915: Use port clock to set correct N value

Use port_clock to check the clock values in n/cts lookup table instead
of crtc_clock. As port_clock is already adjusted based on color mode set
(8 bit or deep color), this will help in checking clock values for deep
color modes from n/cts lookup table.

Signed-off-by: Aditya Swarup <aditya.swarup@intel.com>
Cc: Clint Taylor <Clinton.A.Taylor@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190627220708.31700-1-aditya.swarup@intel.com

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

@@ -212,13 +212,11 @@ static u32 audio_config_hdmi_pixel_clock(const struct intel_crtc_state *crtc_sta
 static int audio_config_hdmi_get_n(const struct intel_crtc_state *crtc_state,
 				   int rate)
 {
-	const struct drm_display_mode *adjusted_mode =
-		&crtc_state->base.adjusted_mode;
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(hdmi_aud_ncts); i++) {
 		if (rate == hdmi_aud_ncts[i].sample_rate &&
-		    adjusted_mode->crtc_clock == hdmi_aud_ncts[i].clock) {
+		    crtc_state->port_clock == hdmi_aud_ncts[i].clock) {
 			return hdmi_aud_ncts[i].n;
 		}
 	}