mmc: renesas_sdhi: remove accessor function for internal_dmac

This accessor function does not help readability but makes it worse.
Because I soon need to read from the registers as well and don't want to
add another function like this, I chose to remove the existing one and
use the accessor directly. I also switch from writeq to writel because
no 64 bit register is actually involved.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Duy Nguyen <duy.nguyen.rh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20221006190452.5316-2-wsa+renesas@sang-engineering.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>