OMAPDSS: DSI: Add new linebuffer size for OMAP5

OMAP5's DSI has a larger line buffer than earlier OMAPs. This patch adds
support for this to the DSI driver.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index a16c8b2..0dc24f2 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -2155,6 +2155,8 @@
 		return 1194 * 3;	/* 1194x24 bits */
 	case 6:
 		return 1365 * 3;	/* 1365x24 bits */
+	case 7:
+		return 1920 * 3;	/* 1920x24 bits */
 	default:
 		BUG();
 		return 0;