ARM: dts: n900: Mark eMMC slot with no-sdio and no-sd flags

Trying to initialize eMMC slot as SDIO or SD cause failure in n900 port of
qemu. eMMC itself is not detected and is not working.

Real Nokia N900 harware does not have this problem. As eMMC is really not
SDIO or SD based such change is harmless and will fix support for qemu.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>