dt-bindings: serial: renesas,scif: Document r9a07g044 bindings

dt-bindings: serial: renesas,scif: Document r9a07g044 bindings

Document R9A07G044 SoC variants, common compatiable string
"renesas,scif-r9a07g044" is added for RZ/G2L and RZ/G2LC SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210514192218.13022-10-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>