NFS: Create an nfs4_server_set_init_caps() function

[ Upstream commit 01dde76e ]

And call it before doing an FSINFO probe to reset to the baseline
capabilities before probing.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Stable-dep-of: b01f21ca ("NFS: Fix the setting of capabilities when automounting a new filesystem")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>