smb: server: add a pr_info() when the server starts running

smb: server: add a pr_info() when the server starts running

We already have a message like:
ksmbd: kill command received
when the server stops running.

This makes it easier for debugging in order to match any possible
warnings/errors in dmesg with restarted server.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>