Add decoder for diag log 0xB114: "LL1 Serving Cell Frame Timing"

[wgreenberg]

This log appears to frequently report the serving cell's current timing advance value, which would be extremely helpful for Rayhunter's ability to determine the location of a possible IMSI catcher.

Unfortunately, as far as I can tell, there's no open source decoder for this format. Because scat has been the foundation of many of Rayhunter's diag decoders, I thought I'd ask for help enabling it here.

Enabling the 0xB114 log on my device yields consistent 72-byte sized values, which I'd be happy to provide as a testbed for scat.

[wgreenberg]

For what it's worth, we ended up finding a decent source on the format of this message and implemented a parser: https://github.com/EFForg/rayhunter/blob/main/lib/src/diag/diaglog/ll1.rs