drm/radeon/dp: Set EDP_CONFIGURATION_SET for bridge chips if necessary

commit 66c2b84b upstream.

Don't restrict it to just eDP panels.  Some LVDS bridge chips require
this.  Fixes blank panels on resume on certain laptops.  Noticed
by mrnuke on IRC.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=42960Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>

drivers/gpu/drm/radeon/atombios_dp.c

@@ -777,10 +777,8 @@ static int radeon_dp_link_train_init(struct radeon_dp_link_train_info *dp_info)
 		radeon_write_dpcd_reg(dp_info->radeon_connector,
 				      DP_DOWNSPREAD_CTRL, 0);
 
-	if ((dp_info->connector->connector_type == DRM_MODE_CONNECTOR_eDP) &&
-	    (dig->panel_mode == DP_PANEL_MODE_INTERNAL_DP2_MODE)) {
+	if (dig->panel_mode == DP_PANEL_MODE_INTERNAL_DP2_MODE)
 		radeon_write_dpcd_reg(dp_info->radeon_connector, DP_EDP_CONFIGURATION_SET, 1);
-	}
 
 	/* set the lane count on the sink */
 	tmp = dp_info->dp_lane_count;