MMC: OMAP: Modifications at N800 MMC board specific file to work MMC multislot support

Modifications at board-n800-mmc.c and board-n800.c files to work with MMC multislot support.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Carlos Eduardo Aguiar <carlos.aguiar@indt.org.br>
Signed-off-by: Tony Lindgren <tony@atomide.com>