This commit adds drivers for Alpine Cache Coherency Unit
and North Bridge Service whose task is to configure
the system fabric and enable cache coherency.
Obtained from: Semihalf
Submitted by: Michal Stanek <mst@semihalf.com>
Sponsored by: Annapurna Labs
Reviewed by: wma
Differential Revision: https://reviews.freebsd.org/D7565
