MMC: Update omap response types

This patch is a fix in order to update MMC response types.
This modification is needed to allow SD card support on OMAP platforms.

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