mmc: dw_mmc: constify dw_mci_idmac_ops in exynos back-end

The of_device_id match data is now marked as const and
must not be modified. This changes the dw_mmc to mark
all pointers passing the dw_mci_drv_data or dw_mci_dma_ops
structures as const, and also marks the static definitions
as const.

drivers/mmc/host/dw_mmc-exynos.c: In function 'dw_mci_exynos_probe':
drivers/mmc/host/dw_mmc-exynos.c:234:11: warning: assignment discards 'const' qualifier from pointer target type [enabled by default]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Abraham <thomas.abraham@linaro.org>
Cc: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>