package/infozip: silent LFS warning

infozip already defines _LARGEFILE_SOURCE and _LARGEFILE64_SOURCE in
some sources files when LARGE_FILE_SUPPORT is set.
Remove them from CFLAGS.

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>