[iMX8MM][MYON2] Add support for Myon II iMX8MM

As ATF binaries provided with Clea OS do not work out of box for some unknown reason, switched to binary (bl31-imx8mm_myon2) from SECO North. These binaries are fully functional, but there is no information how they were produced and from which sources.

Original binary: https://git.seco.com/seco-ne/3rd-party/kuk/imx-mkimage-kuk/-/blob/mkimage-2023-trizeps-myon/iMX8M/bl31-imx8mm.bin