Changes:
o Bugfix: Flow control was causing the device to be destroyed.
o Bugfix: Handle CAIF channel connect failures.
o If the underlying link layer is gone the net-device is no longer removed,
  but closed.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Adding GPRS Net Device for PDP Contexts.
The device can be managed by RTNL as defined in if_caif.h.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>