How it works:
1. Current Meter Source on FC is set to MSP/OSD Slave by user.
2. On reboot FC sends MSP_ANALOG to OSD Slave.
3. OSD Slave listens for incoming MSP as usual.
4. OSD responds to MSP as usual.
6. The FC recevies the data from the OSD Slave and updates the MSP
Current Meter.
* avoiding the use of an unncessesary buffer and memcopy
* the `pushBuf` was a fixed size
* the size didn't correlate to the size of the buffer being passed in.
* avoids repeating the memcpy for each port being used for MSP.
* reduces ram usage.
A quick hack to support config menu on external OSD, consisiting of:
- CMS-OSD partial separation (CMS and OSD reside in a same file: osd.c)
- MSP message injection (take it as server-push in client-server model)