Export LCR meter 'auto' bits as config keys instead of mqflags.

Export LCR meter 'auto' bits as config keys instead of mqflags.

The automatic selections of the measured quantity and equivalent circuit
model are more part of the configuration of the meter than attributes
of the measurement result. To reflect this, model them as config keys
instead of mqflags. This allows a driver that supports remote control to
implement 'set' method for them and has the additional benefit of saveing
two flag bits.