binman: Remove obsolete compressed data header handling

Remove the obsolete compressed data header handling from the utilities
to compress and decompress data. The header is uncommon, not supported
by U-Boot and incompatible with external compressed artifacts.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
Reviewed-by: Simon Glass <sjg@chromium.org>