Patch nfs_serv.c, and maybe other places, for Clang 16 support

[pgoodman]

Clang 16 now has a check that array element type size must be a multiple of array element type alignment. This is problematic when building XNU with Clang 16. For example:

On clang 15 this compiles: https://godbolt.org/z/vTfh1jdzY
On clang 16 this doesn't compile: https://godbolt.org/z/8eMdznce1