Suggestions: Add instruction for Android USB tethering with HoRNDIS.kext in Kernel configuration

To solve the problem of no available Ethernet connection, I add `HoRNDIS.kext` into `EFI\OC\Kexts` and create a child under `Kernel\Add`. The Internet-dependent installer works on my HP i5-6200U laptop(no built-in or external Ethernet port) via Android USB tethering (Lineage 16.0). The screenshots show my configuration on my phone, `config.plist`, and installer.

The HoRNDIS link in https://dortania.github.io/OpenCore-Install-Guide/prerequisites.html#prerequisites only offers `HoRNDIS.pkg`, and there isn't Kernel configuration about `HoRNDIS.kext` in https://dortania.github.io/OpenCore-Install-Guide/config.plist/#adding-your-ssdts-kexts-and-firmware-drivers. `HoRNDIS.kext` could be added into https://dortania.github.io/OpenCore-Install-Guide/ktext.html#ethernet.

Reference:
https://codeword.info/index.php/2021/05/15/mac-os-big-sur-11-3-installing-horndis-to-realize-android/

[HoRNDIS.kext.zip](https://github.com/dortania/bugtracker/files/6900041/HoRNDIS.kext.zip)
[HoRNDIS.kext.zip](https://github.com/dortania/bugtracker/files/6900044/HoRNDIS.kext.zip)