safety feature that prevents quad_gantry_level from trying to do a
correction that might break things - if your probe fires early for
whatever reason and tries to do an 8mm correction in one corner instead
we abort if a correction is over a configurable limit by default 4mm
configurable via `max_adjust` parameter in the config
Signed-off-by: John "Fess" Fessenden <fess@fess.org>