arm64: dts: rockchip: Add missing pinctrl-names to rk3588 boards

arm64: dts: rockchip: Add missing pinctrl-names to rk3588 boards

Several rk3588 board DTS files override pinctrl-0 for i2c, i2s, pcie,
pwm, sdmmc, spdif, spi and uart nodes without re-specifying
pinctrl-names.  While the property is inherited from the base SoC DTSI,
add it explicitly to the board-level overrides for consistency with
other nodes.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Link: https://patch.msgid.link/20260428-dts-rk-frl-enable-gpios-v2-12-924df9db884a@collabora.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>