OMAPDSS: DSI: Add FEAT_DSI_PLL_REFSEL

Add FEAT_DSI_PLL_REFSEL. OMAP5's DSI PLL needs configuration to select
the reference clock to be used. We always use SYSCLK.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dss_features.c b/drivers/video/omap2/dss/dss_features.c
index 177f6e8..4685531 100644
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c
@@ -520,6 +520,7 @@
 	FEAT_FIFO_MERGE,
 	FEAT_BURST_2D,
 	FEAT_DSI_PLL_SELFREQDCO,
+	FEAT_DSI_PLL_REFSEL,
 };
 
 /* OMAP2 DSS Features */