ofed: Define barriers for mips and arm.

I used the strongest barriers available on the architectures, so if
the future analysis show that it is excessive, the barriers could be
relaxed. Still, it is unlikely that it is meaningful to run IB on 32bit
ARM or current MIPS machines, so the change is to make WITH_OFED to pass
tinderbox.

Sponsored by: Mellanox Technologies
Reviewed by: hselasky
Differential revision: https://reviews.freebsd.org/D13329