Add driver for Angst+Pfister O2 sensors FCX-MLD25 & FCX-MLD95 and maybe
more. Tested with FCX-MLD25.
Supports get O2 value, get status, and power management.
Note that in suspended power mode heating output is at 20 %, thus
probably not suited for a battery powered device.
Signed-off-by: Jeppe Odgaard <jeppe.odgaard@prevas.dk>
Jeppe Odgaard