Make WiFi tools optional on the orbic installer too

[untitaker]

This is a followup to #995

That PR only made building wpa-supplicant optional for developers who
effectively test their changes on tplink. Anybody who uses orbic in dev
still had to have a crosscompiler
(#1007 (comment))

This PR now actually makes WiFi tools optional within the orbic
installer too. That step is just skipped entirely if wpa supplicant
wasn't built.

[untitaker]

@jacklund I think that should fix it.

[jacklund]

Tested on my setup by removing the cross-compiler dir from my path, and it worked. I still got the following warnings:

Warning: Skipping building WiFi tools due to missing C crosscompiler.
arm-linux-musleabihf-gcc not found.
Install with: brew install FiloSottile/musl-cross/musl-cross

and

wifi tools were not built into this installer, skipping

but it installed without any issues!!

Thanks @untitaker!