drm/i915/tgl/dsi: Do not override TA_SURE

Do not override TA_SURE timing parameter to
zero for DSI 8X frequency 800MHz or below on
TGL.
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190730073648.5157-4-vandita.kulkarni@intel.com

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

@@ -530,6 +530,7 @@ static void gen11_dsi_setup_dphy_timings(struct intel_encoder *encoder)
 	 * a value '0' inside TA_PARAM_REGISTERS otherwise
 	 * leave all fields at HW default values.
 	 */
+	if (IS_GEN(dev_priv, 11)) {
 		if (intel_dsi_bitrate(intel_dsi) <= 800000) {
 			for_each_dsi_port(port, intel_dsi->ports) {
 				tmp = I915_READ(DPHY_TA_TIMING_PARAM(port));
@@ -544,6 +545,7 @@ static void gen11_dsi_setup_dphy_timings(struct intel_encoder *encoder)
 				I915_WRITE(DSI_TA_TIMING_PARAM(port), tmp);
 			}
 		}
+	}
 
 	if (IS_ELKHARTLAKE(dev_priv)) {
 		for_each_dsi_phy(phy, intel_dsi->phys) {