arm64: dts: renesas: r8a774c0: Add SCIF and HSCIF nodes

Add the device nodes for all RZ/G2E SCIF and HSCIF serial ports,
including clocks, power domains and DMAs.
According to the HW user manual, SCIF[015] and HSCIF[012] are
connected to both SYS-DMAC1 and SYS-DMAC2, while SCIF[34] and
HSCIF[34] are connected to SYS-DMAC0.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>