Fixing Backlight

So what this SSDT does is create a PNLF device for macOS to play with, specifically one with a hardware ID of APP0002. WhateverGreen will handle the rest of the work

No configuration required for most, just drop the prebuilt file into your EFI: SSDT-PNLF

Note: there are some cases where the iGPU is called IGPU in the DSDT, you can double check by searching for both PCI0.GFX0 and PCI0.IGPU. Whichever shows up is your device