drm/omap: Add missing clock sources

enum dss_clk_source does not have values for all clock sources available
on OMAP4+ DSS versions. Add the missing clock sources.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/dss/dss.c b/drivers/gpu/drm/omapdrm/dss/dss.c
index 58d2053..598a51b 100644
--- a/drivers/gpu/drm/omapdrm/dss/dss.c
+++ b/drivers/gpu/drm/omapdrm/dss/dss.c
@@ -108,8 +108,11 @@
 	[DSS_CLK_SRC_FCK]	= "FCK",
 	[DSS_CLK_SRC_PLL1_1]	= "PLL1:1",
 	[DSS_CLK_SRC_PLL1_2]	= "PLL1:2",
+	[DSS_CLK_SRC_PLL1_3]	= "PLL1:3",
 	[DSS_CLK_SRC_PLL2_1]	= "PLL2:1",
 	[DSS_CLK_SRC_PLL2_2]	= "PLL2:2",
+	[DSS_CLK_SRC_PLL2_3]	= "PLL2:3",
+	[DSS_CLK_SRC_HDMI_PLL]	= "HDMI PLL",
 };
 
 static bool dss_initialized;