Restrict FIFO depth to 1 byte on m4k/m5k/m8k/m9k.  Hopefully this prevents hardware faults from happening.
Restrict FIFO depth to 1 byte on m4k/m5k/m8k/m9k.  Hopefully this prevents
hardware faults from happening.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars