bcm963xx: image generation using image tagger

bcm963xx: image generation using image tagger

This adds CFE tagged image generation in the BCM963xx target image Makefile.
It has to generate its own LZMA compressed kernel because CFE is a LZMA nazi.
It also seems that the Broadcom image tagger as well as CFE use AdvanceCOMP,
which is based on a slightly older LZMA SDK. Anyways, some of the code is
GPL, some of it is LGPL, so it might be that Broadcom owes some sources.
Also, LZMA has a bug which causes it to generate different output when you
are using stdin / stdout compared to plain files. I've just worked around
the issue by using plain files.

Signed-off-by: Axel Gembe <ago@bastart.eu.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@11171 3c298f89-4303-0410-b956-a3cf2f4a3e73