ieee802154: fix dgram socket sendmsg()
802.15.4 datagram sockets do not currently have a compliant sendmsg().
The destination address supplied is always ignored, and in unconnected
mode, packets are broadcast instead of dropped with -EDESTADDRREQ. This
patch fixes 802.15.4 dgram sockets to be compliant, i.e.
!conn && !msg_name => -EDESTADDRREQ
!conn && msg_name => send to msg_name
conn && !msg_name => send to connected
conn && msg_name => -EISCONN
Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>