arm64: dts: renesas: rzv2mevk2: Add uart0 pins

Add uart0 pins in pinctrl node and update the uart0 node
to include pinctrl and uart-has-rtscts properties.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230209131422.192941-1-biju.das.jz@bp.renesas.com


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