at86rf2xx: remove ng_ prefix

Makefile.dep

boards/iot-lab_M3/include/at86rf2xx_params.h

boards/mulle/include/at86rf2xx_params.h

boards/samr21-xpro/include/at86rf2xx_params.h

drivers/Makefile.include

drivers/at86rf2xx/Makefile

drivers/at86rf2xx/at86rf2xx.c

drivers/at86rf2xx/at86rf2xx_getset.c

drivers/at86rf2xx/at86rf2xx_internal.c

drivers/at86rf2xx/at86rf2xx_netdev.c

drivers/at86rf2xx/include/at86rf2xx_internal.h

drivers/at86rf2xx/include/at86rf2xx_netdev.h

drivers/at86rf2xx/include/at86rf2xx_registers.h

drivers/include/at86rf2xx.h

drivers/ng_at86rf2xx/include/ng_at86rf2xx_registers.h

sys/auto_init/auto_init.c

sys/auto_init/netif/auto_init_ng_at86rf2xx.c

tests/driver_at86rf2xx/Makefile

tests/driver_at86rf2xx/at86rf2xx_params.h

tests/driver_at86rf2xx/auto_init_ng_netif/netif_app.c