NFSv4.2: another fix for listxattr

Currently, when the server supports NFS4.1 security labels then
security.selinux label in included twice. Instead, only add it
when the server doesn't possess security label support.

Fixes: 243fea13 ("NFSv4.2: fix listxattr to return selinux security label")
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Link: https://lore.kernel.org/r/20250722205641.79394-1-okorniev@redhat.com


Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>