arm64: dts: allwinner: a64: Add missing PIO clocks

The pinctrl binding mandates that we have the three clocks fed into the PIO
described.

Even though the old case is still supported for backward compatibility, we
should update our DTs to fix this.

Fixes: 6bc37fac ("arm64: dts: add Allwinner A64 SoC .dtsi")
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>