OMAP: DSS2: Add FEAT_VENC_REQUIRES_TV_DAC_CLK

OMAP3430 requires an 96MHz clock to VENC's DAC, but no other OMAP needs
it.

Add a new feature, FEAT_VENC_REQUIRES_TV_DAC_CLK, which tells if the
clock is needed on this platform, and use that feature in venc.c to
decide if the clock needs enabling.

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 1c18888..a588380 100644
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c
@@ -286,7 +286,8 @@
 		FEAT_LCDENABLESIGNAL | FEAT_PCKFREEENABLE |
 		FEAT_FUNCGATED | FEAT_ROWREPEATENABLE |
 		FEAT_LINEBUFFERSPLIT | FEAT_RESIZECONF |
-		FEAT_DSI_PLL_FREQSEL | FEAT_DSI_REVERSE_TXCLKESC,
+		FEAT_DSI_PLL_FREQSEL | FEAT_DSI_REVERSE_TXCLKESC |
+		FEAT_VENC_REQUIRES_TV_DAC_CLK,
 
 	.num_mgrs = 2,
 	.num_ovls = 3,