The recent fix 0506d406 made obvious that
error values were not being propagated through the AX.25 stack.  To help
with that this patch marks all kmalloc users in the AX.25, NETROM and
ROSE stacks as __must_check.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>