[RFC v3] Better BE support for ARM

[Ben Dooks]

This is a smaller version of the previous series that adds some fixes
for ARM big endian (BE8) mode on some of the latest ARMv7 systems as
well as fix a few issues that where found whilst doing this.

The new series should be less intrusive, as we alter less and use an
assembly macro to remove anything we do not need if we are not in BE8
mode. If it was not for secondary CPU initialisations and resume paths
we could do this with a pre-boot shim for loading from LE boot loaders.x

Since the issue of the ATAGS endian-ness is still in discussion, this
has been removed from the series. If the system was booted from an LE
enviromnent which uses FDT, then this patch set should work. The ATAGS
code will be posted as a separate series.

The fixes for ASID allocation when big endian has already been sent to
the patch system.