drm/amd/display: write segment pointer with mot enabled for mst

[Why]
Some mst branches NAK's segment pointer writes with mot disabled.
So reset of segment pointer to 0 should be performed with mot enabled.

[How]
Write segment pointer of mst branch devices with mot enabled.

Reviewed-by: Cruise Hung <cruise.hung@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: Meenakshikumar Somasundaram

drivers/gpu/drm/amd/display/dc/link/link_factory.c

@@ -817,9 +817,6 @@ static bool construct_dpia(struct dc_link *link,
 
 	link->psr_settings.psr_version = DC_PSR_VERSION_UNSUPPORTED;
 
-	/* Some docks seem to NAK I2C writes to segment pointer with mot=0. */
-	link->wa_flags.dp_mot_reset_segment = true;
-
 	return true;
 
 ddc_create_fail:

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c

@@ -1867,6 +1867,12 @@ static bool retrieve_link_cap(struct dc_link *link)
 	link->dpcd_caps.is_mst_capable = read_is_mst_supported(link);
 	DC_LOG_DC("%s: MST_Support: %s\n", __func__, str_yes_no(link->dpcd_caps.is_mst_capable));
 
+	/* Some MST docks seem to NAK I2C writes to segment pointer with mot=0. */
+	if (link->dpcd_caps.is_mst_capable)
+		link->wa_flags.dp_mot_reset_segment = true;
+	else
+		link->wa_flags.dp_mot_reset_segment = false;
+
 	get_active_converter_info(ds_port.byte, link);
 
 	dp_wa_power_up_0010FA(link, dpcd_data, sizeof(dpcd_data));