95fcoe: Add the rd.nofcoe option to disable the FCoE module from the command line

95fcoe: Add the rd.nofcoe option to disable the FCoE module from the command line

Images built with the fcoe module will always run the lldpad
service as part of their pre-trigger scripts if the network
is active. This prevents network installations in
environments where, for security reasons, LLDPDU frames
cause a switchport shutdown.

Add a new rd.nofcoe option to cause dracut to skip the
lldpad.sh script and the entire 95-fcoe module.

Signed-off-by: Patrick Talbert <ptalbert@redhat.com>