csma MAC driver queues outgoing frames, returning an OK status code immediately.
This defeats logic in sicslowpan fragmentation driver that drops remaining fragments
on send failure. The result is packets reported as sent successfully when they were
not, fragments sent that cannot be reassembled by receiver, packets dropped before
the first fragment even reached the radio driver.
nullmac MAC driver sends frames synchronously, resulting in sicslowpan driver working
as intended.
The MAC driver used by 802.15.4 is selectable now, nullmac is default but csma can be
used instead.
Change-Id: I261d551421a8f55634acb1c528f8f82bea49332d
Signed-off-by: Vlad Lungu <vlad.lungu@windriver.com>
20a4720b93