NFS: introduce nfs_mount_info struct for calling nfs_mount()

Clean up: convert nfs_mount() to take a single data structure argument to make
it simpler to add more arguments.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --cc fs/nfs/internal.h
Simple merge

diff --cc fs/nfs/mount_clnt.c
Simple merge

diff --cc fs/nfs/nfsroot.c
Simple merge

diff --cc fs/nfs/super.c
Simple merge