ksmbd: smbd: change the default maximum read/write, receive size

[ Upstream commit 4d02c4fd ]

Due to restriction that cannot handle multiple
buffer descriptor structures, decrease the maximum
read/write size for Windows clients.

And set the maximum fragmented receive size
in consideration of the receive queue size.

Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>