smb3: fix touch -h of symlink

For example:
      touch -h -t 02011200 testfile
where testfile is a symlink would not change the timestamp, but
      touch -t 02011200 testfile
does work to change the timestamp of the target

Suggested-by: David Howells <dhowells@redhat.com>
Reported-by: Micah Veilleux <micah.veilleux@iba-group.com>
Closes: https://bugzilla.samba.org/show_bug.cgi?id=14476


Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>