sys/conf: Fix arm64 vmm_nvhe dependencies

These files include a vmm_hyp equivalent file but don't have a
dependency recorded. Fix this by manually adding this dependency.

This is only a problem in a non-GENERIC configuration as normally vmm
is loaded as vmm.ko.

Reviewed by: imp
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D51822