Pull up following revision(s) (requested by yamaguchi in ticket #789):

sys/dev/isa/wbsio.c: revision 1.24

Use spin mutex to fix a panic

The GPIO part of wbsio(4) has a lock to keep the register access
order. In addition to the lock, gpio(4) has a look to prevent
multiple control through gpio_pin_ctl(). Those locks hold at
once when gpio_pin_ctl() is called, and the lock of gpio(4) hold
before that of wbsio(4).

Therefore, the wbsio(4) has to use spin lock if gpio(4) uses
spin lock.

(martin)