Add ppc64 support

There were a couple of issues in the trampoline code that
needed fixing for 64bit.

Signed-off-by: Anton Blanchard <anton@samba.org>
Add ppc64 little endian support

We were missing some byteswapping of device tree properties.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cap memory at 2GB on ppc64 partitioned boxes.

We cap memory at 2GB for the non partitioned case but
forgot to do the same for partitioned boxes.