drivers/intel/gma/acpi: Replace Increment() with ASL 2.0 syntax

Replace `Increment(a)` with `a++`.

Change-Id: If0c11f43713bf7afec6dd600289776eefd1331e8
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60580
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>

src/drivers/intel/gma/acpi/common.asl

@@ -58,7 +58,7 @@
 			Store (BRID (XBQC ()), Local0)
 			If (LNotEqual (Local0, SizeOf(BRIG) - 1))
 			{
-				Increment (Local0)
+				Local0++
 			}
 			XBCM (DerefOf (BRIG[Local0]))
 		}

src/drivers/intel/gma/acpi/configure_brightness_levels.asl

@@ -134,7 +134,7 @@
 					}
 				}
 
-				Increment (Local1)
+				Local1++
 			}
 
 			/* Didn't find greater/equal value: use the last */