package/lz4: bump version to r131

systemd v228 requires lz4 >= 125

Signed-off-by: Gabe Evans <gabe@hashrabbit.co>
[Thomas: only pass PREFIX=/usr at install time instead of using
LZ4_MAKE_OPTS, and also pass it for the host installation.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>