remaining changes for low latency RC_OVERRIDE

Hi Tridge,

Thanks for making that build of the low latency stuff, but I think the binary / your current smallpacket-wip branch was missing https://github.com/tridge/SiK/pull/9.  This change is important (and I guess I should have just glommed it into the original pull request https://github.com/tridge/SiK/pull/7).  It makes the rc_override shortcut also work for the first rc_override packet in the fifo, not just the later ones.

I've make this new PR by pulling down your current smallpacket-wip, merging in my branch, bumping version number to 1.9, building the binaries and testing on my radios.  Would you mind doing a new build with this change?  (I can't write to the firmware tree)