arm: dts: imx8mm: sync dts from Linux Kernel 5.10-rc6

There have been some updates to the device tree since 5.6.
This also includes some clocks, and makes it easier to keep
board device tree files in sync with Linux

Signed-off-by: Adam Ford <aford173@gmail.com>
Acked-by: Peng Fan <peng.fan@nxp.com>