ARM: 7719/1: mmc: mmci: Support for CMD23

Support added for transmission of CMD23 during multi block read or
write. In order to activate this feature, MMC_CAP_CMD23 flag needs
to be enabled in the capabilities field. Note that CMD23 support is
mandatory to support features like reliable write, data tag, context
ID, packed command.

This patch is based upon a patch from Saugata Das.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>