arm64: dts: allwinner: a64: Add gpio bank supply for A64-Olinuxino

Add the regulators for each bank on this boards.
For VCC-PL only add a comment on what regulator is used. We cannot add
the property without causing a circular dependency as the PL pins are
used to talk to the PMIC.

Signed-off-by: Emmanuel Vadot <manu@freebsd.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>