Introduce support for Annapurna Alpine CCU and NB devices

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