Without a dm to handle the session management systemd-logind can make it
difficult for X to gain ownership of devices and behave properly.
Since X seems to work without enabling systemd-logind, always disable it for
now, and we can revisit it if we ever want to try to take advantage of
multi-user sessions/seats.
[Yocto # 7100]
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
