microblaze: Fix unaligned.h for endians

Also support little endian MB.

Signed-off-by: Michal Simek <monstr@monstr.eu>
Acked-by: Mike Frysinger <vapier@gentoo.org>

Move architecture-specific includes to arch/$ARCH/include/asm

This helps to clean up the include/ directory so that it only contains
non-architecture-specific headers and also matches Linux's directory
layout which many U-Boot developers are already familiar with.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>