fix external analog module power control

[ligenxxxx]

#622

[pitts-mo]

This build breaks Analog RX power control for original HDzero goggle. The Analog RX module of original HDZero goggle will always stay powered and will never shut off.

#560 attempted to fix analog RX power after goggle 2 merge broke Analog RX power for goggle 1. I suspected some deeper digging was required for goggle2 but I do not have goggle 2 test hardware and there was limited feedback :-/

I have verified v9.6.0-rc1 restores the Analog RX Auto power feature to the original HDZero Goggle.

[ligenxxxx]

@pitts-mo Please try again; I think I’ve fixed it.

[pitts-mo]

Better :-) But still see two issues.

1. does not set off state after boot. eg: if booted into HDZero RX analog module will not power off.
   In this case selecting another sources will not fix it. I must specifically select the analog module. Then external RX power will turn off as soon as I exit live view.

2. analog module is now turned off immediately when exiting live view.
   In this case even accessing the menu will power off the VRX and user needs to wait for VRX reboot before video resumes. I do imagine it might be desirable to quickly power off the external module in some cases of quick input switching. But It seems we should only turn off external module power after the source has been switched.

Thank you @ligenxxxx