handful of improvements to firmware - rename write_pots as write_ad5122, drop 0x0E and 0xEE in favor of 0x51. 0x50, fix default vreq type to not waste cycles, remove DISABLED conditional from main streaming path
whoops - chb should change chb switch
move all config into firmware
fix firmware for repeated scans in different modes
Abort pending transfers when resetting sampling state.

Resetting this state allowed the main loop to submit transfers on
endpoints that already had transfers pending. If the host had already
begun those transfers, this resulted in data corruption.
Fix uninitialized variable