drivers: renesas: rzg: Switch using common ddr code

Switch using common ddr driver code from renesas/common/ddr directory
for RZ/G2M SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Change-Id: I807dcb0bc5186bd32bc1c577945d28634bb10e1f
15 files changed