Add initial DTSI for RZ/G2{L,LC} SoC's.

File structure:
r9a07g044.dtsi  => RZ/G2L family SoC common parts
r9a07g044l1.dtsi => RZ/G2L R9A07G044L1 SoC specific parts
r9a07g044l2.dtsi => RZ/G2L R9A07G044L2 SoC specific parts
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210609153230.6967-11-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>