altos: Use max of 64 previous orient values when checking pyro limits

altos: Use max of 64 previous orient values when checking pyro limits

Instead of checking just a single measurement to see if the
orientation is outside of the desired limits, use the maximum of 64
previous values to that rapidly changing orientation won't
accidentally enable a pyro channel if sampled at the 'wrong time'.

Signed-off-by: Keith Packard <keithp@keithp.com>