Just checking "does the chip have an EMAC" doesn't work - there are
targets using those chips which do not have an Ethernet connector and
don't provide the necessary surrounding infrastructure (eg DISCO_F429ZI,
not providing the board emac config call, and HEXIWEAR not providing PHY
info).
Make the targets that actually do want EMAC define their own local
Freescale_EMAC and STM_EMAC labels, and move the drivers into
the corresponding TARGET_ directories, removing the #ifdefs.