Make pppoe_create() actually store the passed service name and
concentrator name, so that they are passed in the PADI/PADR/PADS
packets.
Assume that the user application won't be freeing the strings and just
copy the string pointers, therefore remove the mem_free() in
pppoe_destroy().
Since only the pointers are copied now, make them 'const' in
pppoe_softc.
Signed-off-by: Sylvain Rochet <gradator@gradator.net>
c02fea0961