The periph_dma is not pulled in automatically for all applications.
Applications willing to use the configured peripherals with periph_dma
for a given board will have to include the feature explictly in their
Makefile.

It was causing unrelated issues as threads got de-scheduled while
calling printf and this was not handled properly in tests at that
moment.

Used with UART and SPI peripheral

This got lost somehow in 10e9336c. Without this fix gnrc_netdev_default
does not include the at86rf2xx module.

Additionally the dependencies for GNRC specific modules are centralized in Makefile.dep.

* deploy extended operation mode
* cleanup
* implement netdev 802154.h interface