ARM: dts: sun8i: a83t: bananapi-m3: increase vcc-pd voltage to 3.3V

Since commit d7c5f686 ("ARM: dts: sun8i: a83t: bananapi-m3: Add
AXP813 regulator nodes") my BPIM3 no longer works at gigabit speed.

With the default setting, dldo3 is regulated at 2.9v which seems
sufficient for the PHY but the aforementioned commit drops it to 2.5V
which is insufficient. Note that this behaviour is random for all BPIM3.
Some work with 2.5V, but some don't.

Finnaly, someone from Bananapi confirmed that this regulator must be set
to 3.3V.

Fixes: d7c5f686 ("ARM: dts: sun8i: a83t: bananapi-m3: Add AXP813
		      regulator nodes")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
[wens@csie.org: Reworked commit message]
Signed-off-by: Chen-Yu Tsai <wens@csie.org>