arm64: allwinner: a64: change TERES-I DLDO3's name to start with "vdd"

Originally the name of the DLDO3 regulator on TERES-I is "eDP12", which
is not consistent with other regulator names.

Change it to "vdd-edp", in order to make it more consistent.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>