Also check if input variable is 0 and fix indentation

This will be used to make updating firmware on boot for vehicles with
no safety switch possible without power cycling. The startup script
needs to be able to force safety on to allow the reboot to work.

the ms5611 can be on two addresses. The driver handles this, not the
board config

this uses the same table driven approach as the hmc5883 driver, and
allows for a ms5611 baro on any of the 4 bus combinations. A simple
"ms5611 start" will start all baros that are found.

Ros messagelayer merge attctrl posctrl