arm64: Hyper-V: enablement for ARM64 in Hyper-V (Part 2)

This is the second part of the ARM64 Hyper-V enablement.
These changes here are mostly with Make, release changes and also
changes required in vmbus.c hyperv.c and common files in hyperv.

Reviewed by: whu
Tested by: Souradeep Chakrabarti <schakrabarti@microsoft.com>
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D36467