Building FreeBSD kernel for the Watchguard Firebox M300

- make buildkernel KERNCONF=QORIQ64
- mkubootimage -A powerpc -O linux -a 0 -e 0x12000 -C none -n FreeBSD -d /path/to/built/kernel kernel.uImage
- Also need to build the DTB, getting the DTS from OpenWRT:
  - env MACHINE=powerpc ./sys/tools/fdt/make_dtb.sh $PWD
    /path/to/watchguard_m300.dts /tftpboot/m300.dtb

On the m300:
- setenv ethact FM1@DTSEC10 (if plugged into the first port)
- tftpboot $fdtaddr m300.dtb
- tftpboot $loadaddr kernel.uImage
- bootm $loadaddr - $fdtaddr