mmc: renesas_sdhi_internal_dmac: Add r8a774b1 support

This patch adds SDHI support for RZ/G2N (R8A774B1) SoC.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>