radio.fem.rxgain setting is not persisted in 1.17

[Magalex2x14]

@ErikBrown2 reports that radio.fem.rxgain setting is not persisted in 1.17 - it is enabled again after reboot.
There is also confirmation from another 4.3 owner.

[jschrempp]

Is this the same as #3137

[Magalex2x14]

Is this the same as #3137

Yeah, seems like #3137 have solution for this, thanks!