mb/clevo/l140cu: add panel settings to the dt and hook up GMA ACPI

Add the panel settings dumped from vendor firmware and hook up
drivers/intel/gma, which will be required for brightness control.

Keyboard brightness control still requires ACPI code. This will be done
in a separate change later.

Test: Panel gets enabled when the payload starts on Clevo L141CU.

Change-Id: I7977a2271da72c142b025b4631318d1a39adfb13
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48750
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/mainboard/clevo/cml-u/dsdt.asl

@@ -18,6 +18,7 @@ DefinitionBlock(
 	{
 		#include <soc/intel/common/block/acpi/acpi/northbridge.asl>
 		#include <soc/intel/cannonlake/acpi/southbridge.asl>
+		#include <drivers/intel/gma/acpi/default_brightness_levels.asl>
 	}
 
 	#include <southbridge/intel/common/acpi/sleepstates.asl>

src/mainboard/clevo/cml-u/variants/l140cu/devicetree.cb

@@ -65,7 +65,17 @@ chip soc/intel/cannonlake
 	device domain 0 on
 		subsystemid 0x1558 0x1401 inherit
 		device pci 00.0 on	end	# Host Bridge
-		device pci 02.0 on	end	# Integrated Graphics Device
+		device pci 02.0 on		# Integrated Graphics Device
+			register "gfx" = "GMA_DEFAULT_PANEL(0)"
+			register "panel_cfg" = "{
+				.up_delay_ms		=  200,
+				.down_delay_ms		=   50,
+				.cycle_delay_ms		=  500,
+				.backlight_pwm_hz	= 1000,
+				.backlight_on_delay_ms	=    1,
+				.backlight_off_delay_ms	=    1,
+			}"
+		end
 		device pci 04.0 on		# SA Thermal device
 			register "Device4Enable" = "1"
 		end