mb/system76: Use default GMA brightness levels

This reverts commit 1f81af5 ("mb/system76: Add custom backlight
levels for Intel GMA").

Defaulting to 40% can make the screen hard to read as System76's
firmware setup uses white text on a gray background.

Change-Id: I13ab3797319c4db6e800737a3f4e4344e3b588f3
Signed-off-by: Tim Crawford <[email protected]>

Author: crawfxrd

src/mainboard/system76/adl/acpi/backlight.asl

@@ -11,8 +11,6 @@
 Scope (\_SB) {
 	#include "sleep.asl"
 	Scope (PCI0) {
-		#include "backlight.asl"
-
 #if CONFIG(DRIVERS_GFX_NVIDIA)
 		Scope (PEG2) {
 			#include <drivers/gfx/nvidia/acpi/tigerlake.asl>

src/mainboard/system76/adl/acpi/mainboard.asl

@@ -20,6 +20,7 @@ DefinitionBlock(
 		#include <soc/intel/common/block/acpi/acpi/northbridge.asl>
 		#include <soc/intel/alderlake/acpi/southbridge.asl>
 		#include <soc/intel/alderlake/acpi/tcss.asl>
+		#include <drivers/intel/gma/acpi/default_brightness_levels.asl>
 	}
 
 	#include <southbridge/intel/common/acpi/sleepstates.asl>

src/mainboard/system76/adl/dsdt.asl

@@ -6,9 +6,6 @@
 
 Scope (\_SB) {
 	#include "sleep.asl"
-	Scope (PCI0) {
-		#include "backlight.asl"
-	}
 }
 
 Scope (\_GPE) {

src/mainboard/system76/cml-u/acpi/backlight.asl

@@ -19,6 +19,7 @@ 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/system76/cml-u/acpi/mainboard.asl

@@ -9,7 +9,6 @@
 Scope (\_SB) {
 	#include "sleep.asl"
 	Scope (PCI0) {
-		#include "backlight.asl"
 		Device (PEGP) {
 			Name (_ADR, CONFIG_DRIVERS_GFX_NVIDIA_BRIDGE << 16)
 			#include <drivers/gfx/nvidia/acpi/coffeelake.asl>

src/mainboard/system76/cml-u/dsdt.asl

@@ -18,6 +18,7 @@ DefinitionBlock(
 	Device (\_SB.PCI0) {
 		#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>