Enables MMC/SD card support option on n800_defconfig to use MMC multislot support.
Signed-off-by: Carlos Eduardo Aguiar <carlos.aguiar@indt.org.br>

Refreshed to apply after Lauri's patch. Also left out
CONFIG_MMC_BLOCK_BOUNCE as omap MMC supports SG.
Signed-off-by: Tony Lindgren <tony@atomide.com>