smb: server: take the recv_credit_target from the negotiate req and always limit...

smb: server: take the recv_credit_target from the negotiate req and always limit the range

The clients sends the initial recv_credit_target in the negotiate req,
so we should use that.

We also limit the range between 1 and our local defined
sp->recv_credit_max. This will simplify further logic changes.

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>