powerpc/pseries: Little endian fixes for post mobility device tree update

[ Upstream commit f6ff04149637723261aa4738958b0098b929ee9e ]

We currently use the device tree update code in the kernel after resuming
from a suspend operation to re-sync the kernels view of the device tree with
that of the hypervisor. The code as it stands is not endian safe as it relies
on parsing buffers returned by RTAS calls that thusly contains data in big
endian format.

This patch annotates variables and structure members with __be types as well
as performing necessary byte swaps to cpu endian for data that needs to be
parsed.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Cyril Bur <cyrilbur@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>