stout: Add native gfx init

Tested during FOSDEM.

Change-Id: Id095364d6e4735256e54a68ea9ae677355dd386a
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: https://review.coreboot.org/13532
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/google/stout/devicetree.cb b/src/mainboard/google/stout/devicetree.cb
index 1992664..97db8ae 100644
--- a/src/mainboard/google/stout/devicetree.cb
+++ b/src/mainboard/google/stout/devicetree.cb
@@ -14,6 +14,12 @@
 	register "gpu_panel_power_backlight_on_delay" = "2100"  # T5: 210ms
 	register "gpu_panel_power_backlight_off_delay" = "2100" # TD: 210ms
 
+	# For native gfx
+	register "gfx.use_spread_spectrum_clock" = "0"
+	register "gfx.link_frequency_270_mhz" = "1"
+	register "gpu_cpu_backlight" = "0x1155"
+	register "gpu_pch_backlight" = "0x06100610"
+
 	device cpu_cluster 0 on
 		chip cpu/intel/socket_rPGA989
 			device lapic 0 on end