arm/arm64: dts: renesas: Drop unused .dtsi

These .dtsi files are not included anywhere in the tree and can't be
tested.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Acked-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20251212203226.458694-1-robh@kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: robherring