Create net_l2_send() function which will be called by each L2
sending function so that we can catch all the network packets
that are being sent. Some L2 layers send things a bit differently,
so in those cases call the net_capture_send() directly by the L2
layer.
Add network packet capture call in receive side after the pkt has
been received by the RX queue handler. This avoids calling the
net_capture_send() from ISR context.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>