NFSv4: Don't check for OPEN feature support in v4.1

fattr4_open_arguments is a v4.2 recommended attribute, so we shouldn't
be sending it to v4.1 servers.

Fixes: cb78f9b7 ("nfs: fix the fetch of FATTR4_OPEN_ARGUMENTS")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # 6.11+
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>