arm64: dts: renesas: r8a774c0: Fix SCIF5 DMA channels

Correct the DMA channels for SCIF5 from 16..47 to 0..15, as was done for
R-Car E3.

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Fixes: 2660a6af

 ("arm64: dts: renesas: r8a774c0: Add SCIF and HSCIF nodes")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>