iommu/ipmmu-vmsa: Hook up R8A774A1 DT maching code

Add support for RZ/G2M (R8A774A1) SoC IPMMUs.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Joerg Roedel <jroedel@suse.de>