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: e20396d6 ("arm64: dts: renesas: Add initial DTSI for RZ/G3S SoC")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/884c683fb6c1d1bf7d0d383a8df8f65a0a424dc7.1718890849.git.geert+renesas@glider.be