rcar_gen3: drivers: ddr-a: Replace {Read,Write}Reg_32() with mmio_{read,write}_32()

Replace ad-hoc register accessors with generic ones, remove the ad-hoc
implementation. No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: I21446a00a38c6a39d6a48652c34f59814074e831
3 files changed