Fix possible loading of failsafes due to out-of-order time assignment

Since linkLossTimeMs is assigned after timeMs, its value can be greater and so when subtracted from timeMs roll over and produce a large positive number greater than rx_config.failsafeDelay, loading failsafes immediately even though they should not be.

Failsafes are loaded here: https://github.com/DTFUHF/openLRSng/blob/77dc239adea9cae1556fba6ed4df99ae30462f4b/RX.h#L665