mmc: sdhci-of-arasan: Add a single data structure to incorporate pdata and soc_ctl_map

Currently, the driver passes platform data as a global structure
and uses the .data of of_device_id to pass the soc_ctl_map. To
make the implementation more flexible add a single data structure
that incorporates both of the above and pass it in the .data of
of_device_id.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>