ARM: dts: sun5i: reference-design-tablet: Enable AXP209 AC and battery

The reference design tablet has the DC jack wired to AXP209's ACIN.
As a tablet, it also has an internal LiPo battery, wired to the PMIC's
battery charger.

Enable both.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>