arm64: dts: imx8mn: add 8MNANOD3L-EVK device tree

arm64: dts: imx8mn: add 8MNANOD3L-EVK device tree

Add a device tree for the 8MNANOD3L-EVK eval board which features an
IMX8MN SoC. It is similar to the 8MNANODLPD4-EVK eval board except it
has an IMX8MN UltraLite SoC and DDR3L memory. It esp. differs in the
PMIC configuration because the SoC has a smaller package and thus the
ARM core voltage is combined with the SoC voltage and the DDR voltage
is 1.35V for the DDR3L memory.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>