MMC: OMAP: Remove cover switch handling to allow adding multislot support

This patch removes the MMC cover switch handling temporarily
to make following multislot patches cleaner.

MMC cover switch handling will be added back in later patches
after adding basic multislot support.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Carlos Eduardo Aguiar <carlos.aguiar@indt.org.br>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>