mmc: dw_mmc: Support predefined mutiple block transfers

This patch adds the support for predefined multiple block r/w.
dw_mmc can support MMC_CAP_CMD23 capability.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>