Add linux-firmware install option for Navi-10 graphics cards about archfi

[MatMoul]

Thanks for the issue,

linux-firmware needs to be added to my project but i don't know if it should be part of archfi or archdi.

If the installation with archfi is boot correctly in console without linux-firmware, this one must be integrated in archdi.

If some people encounter issue to boot with the new install without linux-firmware, it need to be an optional part of archfi

[Mitnitsky]

IMO it should be added to archdi script because i've had no problem logging into tty after installing archdi and installing the linux-firmware manually so it shouldn't be a part of the archfi install

[MatMoul]

The new release include now kernel selection and linux-firmware