FrogPilot handles the GM SystemPowerMode message on both bus 0 and bus 2
(SDGM cars send it on bus 2). C3XL-dev only checked bus 0, so GM cars with
0x1F1 on bus 2 never set ignition_can and the device would not auto power-on.
Mirror FrogPilot: check 0x1F1 on bus 2 as well, keep other exceptions bus-0 only.
comma