ARM: dts: sun5i: Add axp152 pmic node to mk802

Add a node describing the axp152 pmic to the mk802 dts, note there are
no regulator nodes as we do not yet support the regulators on the
axp152.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>