ARM: dts: imx7ulp-com: Add initial support for i.MX7UP COM board

The Embedded Artists COM board is based on NXP i.MX7ULP.

It has a BD70528 PMIC from Rohm with discrete DCDC powering option and
improved current observability (compared to the existing NXP i.MX7ULP EVK).

Add the initial support for the board.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>