Add DMA Controller driver for RZ/G2L SoC.

Based on the work done by Chris Brandt for RZ/A DMA driver.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20210806095322.2326-4-biju.das.jz@bp.renesas.comSigned-off-by: Vinod Koul <vkoul@kernel.org>