ARM: imx: Enable CAAM on DH i.MX8M Plus DHCOM

Enable CAAM in U-Boot to make crypto available early in the boot process.

This has a side-effect that in case an older kernel version contains a
broken CAAM initialization timeout code, initialization in bootloader
will help that old kernel version function correctly.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>