drm/omap: omap_display_timings: rename vbp to vback_porch

In preparation to move the stack to use the generic videmode struct for
display timing information rename the vbp member to vback_porch.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c

@@ -51,7 +51,7 @@ static struct omap_video_timings td028ttec1_panel_timings = {
 	.hback_porch	= 8,
 	.vfront_porch	= 4,
 	.vsync_len	= 2,
-	.vbp		= 2,
+	.vback_porch	= 2,
 
 	.vsync_level	= OMAPDSS_SIG_ACTIVE_LOW,
 	.hsync_level	= OMAPDSS_SIG_ACTIVE_LOW,