Turn the explicitly enabled zlib support into an enabled by default
PACKAGECONFIG, and add Zstd support (disabled by default).
(From OE-Core rev: 6dd6184f01d79ebd26347a6006f92a5b5906ee3e)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>