arm64: Hyper-V: Add vPCI and Mellanox driver modules into build
These changes in conf and std.hyperv files got missed in previous commit.
Reviewed by: whu
Tested by: whu
Obtained from: Souradeep Chakrabarti <schakrabarti@microsoft.com>
Sponsored by: Microsoft
Differential Revision: https://reviews.freebsd.org/D38529