arm64: dts: renesas: r8a774c0: Add CMT device nodes

This patch adds CMT{0|1|2|3} device nodes for r8a774c0 SoC.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>