decompress any data, whatever is the radio decompressed data / compressed
data.
It fixes the last issues with fast_ipsec and ipcomp.
While here, bzero -> memset, bcopy -> memcpy, FREE -> free
Reviewed a long time ago by sam@
code is derived from Sam Leffler's FreeBSD port of OCF, which is in
turn a port of Angelos Keromytis's OpenBSD work.
Credit to Sam and Angelos, any blame for the NetBSD port to me.