ksmbd: update Kconfig to note Kerberos support and fix indentation

[ Upstream commit d280a958 ]

Fix indentation of server config options, and also since
support for very old, less secure, NTLM authentication was removed
(and quite a while ago), remove the mention of that in Kconfig, but
do note Kerberos (not just NTLMv2) which are supported and much
more secure.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>