ARM: 6307/1: mmci: allow the card detect GPIO value not to be inverted

On some platforms, the GPIO value from the gpio_cd pin doesn't need to
be inverted to get it active high.  Add a cd_invert platform data
parameter and change existing platforms using GPIO for CD (only
Realview) to enable it.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>