Add the missing fifth interrupt to the device node that represents the
ARM architected timer.  While at it, add an interrupt-names property for
clarity,

Fixes: 68a45525 ("arm64: dts: renesas: Add initial DTSI for RZ/G2{L,LC} SoC's")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/21f556eb7e903d5b9f4c96188fd4b6ae0db71856.1718890849.git.geert+renesas@glider.be