handle more than 2 blacklisted modules in cmdline
Created by: mmlb
example:
❯ docker run --rm -ti alpine
/ # KOPT_blacklist=igb,ixgbe,tg3
/ # for i in ${KOPT_blacklist/,/ }; do echo "blacklist $i"; done
blacklist igb
blacklist ixgbe,tg3
/ # for i in ${KOPT_blacklist//,/ }; do echo "blacklist $i"; done
blacklist igb
blacklist ixgbe
blacklist tg3