gnrc_netdev: remove remaining files and references

Makefile.dep

sys/Makefile

sys/include/net/gnrc.h

sys/include/net/gnrc/netdev.h

sys/include/net/gnrc/netdev/eth.h

sys/include/net/gnrc/netdev/ieee802154.h

sys/include/net/gnrc/netdev/raw.h

sys/include/net/gnrc/netdev/xbee_adpt.h

sys/include/net/gnrc/nettype.h

sys/include/net/netopt.h

sys/net/gnrc/link_layer/netdev/Makefile

sys/net/gnrc/link_layer/netdev/gnrc_netdev.c

sys/net/gnrc/link_layer/netdev/gnrc_netdev_eth.c

sys/net/gnrc/link_layer/netdev/gnrc_netdev_ieee802154.c

sys/net/gnrc/link_layer/netdev/gnrc_netdev_raw.c

sys/net/gnrc/link_layer/netdev/gnrc_netdev_xbee.c

tests/driver_sx127x/main.c