nfsd4: fix xdr4 count of server in fs_location4

Fix a bug where nfsd4_encode_components_esc() incorrectly calculates the
length of server array in fs_location4--note that it is a count of the
number of array elements, not a length in bytes.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: 082d4bd7 (nfsd4: "backfill" using write_bytes_to_xdr_buf)
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>