arm64: dts: renesas: r9a07g043u: Add Cortex-A55 PMU node

Enable the performance monitor unit for the Cortex-A55 core on the
RZ/G2UL (r9a07g043u) SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230206001133.28776-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>