old gunzip

[Joakim Tjernlund]

I started to look at impl. the inflate optimization I recently added
to both u-boot and the kernel. The decompress_unzip.c file looks
as it is based on a much older gzip than both u-boot and the linux
kernel. I think rebasing this code on the more recent zlib would
be a improvement. I don't have the time to do that but I can add
the optimization afterwards. Adding the optimization in the
current code looks risky, I can't find my way in there.

 Jocke