ARM: dts: sunxi: Use axp209.dtsi for Olinuxino Lime2

Use axp209.dtsi in sun7i-a20-olinuxino-lime2.dts and correct
some regulators.

DCDC2 is used for vdd-cpu so it should never be bellow 1V and above 1.4V
DCDC3 is used for VDD_INT so same as above.
LD01 is used for the RTC, and should have a typical value of 1.3V
LD02 is used for AVCC and should have a typical value of 3.0V
LD03/4 are used for Port-E/Port-G Power pin, and the schematics recommands
to set them to 2.8V as they can be used for CSI0/1.

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>