nfs: Add some support for POSIX draft ACLs

An internet draft (expected to become an RFC someday)
https://datatracker.ietf.org/doc/draft-ietf-nfsv4-posix-acls
describes an extension to NFSv4.2 to handle POSIX draft ACLs.

This is the fifth of several patches that implement the
above draft.

This one mostly adds an extra argument to two functions
in nfscommon.ko. Unfortunately, these functions are
called in many places, so the changes are numerous, but
straightforward.

Since the internal KAPI between the NFS modules is changed
by this commit, all of nfscommon.ko, nfscl.ko and nfsd.ko
must be rebuilt from sources.

There should be no semantics change for the series at
this point.

(cherry picked from commit 9f49f436a9ec9441dacae8117280a83ddea7b9c6)