arm: dts: imx8mm: sync dts from Linux Kernel 5.6.7

This patch synchronizes the device tree with that from 5.6.7.

This also adds nodes for crypto and ddrc, which makes keeping
the device tree files from individual boards in sync with the
Linux kernel.  This is helpful when boads reference those nodes.

Signed-off-by: Adam Ford <aford173@gmail.com>