drm/modes: Parse overscan properties

Properly configuring the overscan properties might be needed for the
initial setup of the framebuffer for display that still have overscan.
Let's allow for more properties on the kernel command line to setup each
margin.

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e481f1628e3768ca49226ec2115cfa4dfcbd5e4c.1560783090.git-series.maxime.ripard@bootlin.com
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index b22e315..ca745d9 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -1054,6 +1054,11 @@ struct drm_cmdline_mode {
 	 * DRM_MODE_ROTATE_0 and DRM_MODE_ROTATE_180.
 	 */
 	unsigned int rotation_reflection;
+
+	/**
+	 * @tv_margins: TV margins to apply to the mode.
+	 */
+	struct drm_connector_tv_margins tv_margins;
 };
 
 /**