Preserve radio mode when updating tx_iq_phase_cal

[NotherNgineer]

An alternate fix for #2006.

Saves and restores radio "mode" when updating the tx_iq_phase_cal value (versus always putting the radio into Standby mode afterwards)

[gullradriel]

This need live testing, but the code looks good. Thanks !

[Brumi-2021]

Hello thanks to both .
@NotherNgineer , I was considering to pass to the driver side , a new argument (tx or rx ) , but I think your idea is even better.
Much simple and compact.

I just test your binary in the Mic App , and the TX IQ functionality keeps working and you fixed the previous problem about "Rx Audio" .
But further test, (in both units : first in H2+ , but also confirmed with r9 same problem ) showed me a new guru bug ,
If you keep selected "Rx Audio" ON , and switch off the device and switch on again , and goes directly to Mic App ,
you got just tone noise in the headphones and guru halt bug .

But if you switch on , and goes previously to any Rx App, and then goes to Mic App, it works perfectly .
So it seems. it is missing some "mode" init , when first power on the unit and goes directly to Mic App with the "Rx Audio" activated.
It is not a serious blocking bug, because at the moment we have temporal solution, (not leave activated "Rx Audio" inside Mic App, or if you leave it , just launch any Rx Application after booting .

If you can not reproduce it , just let me know about it ,

Cheers.