Add MII support for ADMtek Comet (Linksys LNE100TX v4.1 & others):
* tulip_core.c: add HAS_MII flag to COMET entry in tulip_tbl[]
* timer.c (comet_timer): add missing call to tulip_check_duplex()
and replace inl() calls with tulip_mdio_read() calls
Changes modeled after Donald Becker's tulip.c:v0.98 1/8/2004