uncompress: add config to disable it ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

lib: prompt for uncompression functions ...

Allow the user to manually select the uncompression support
he wants to have so that we have a single point where a user
can see which uncompression support will be compiled in.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

add unlzo support ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>