The priv is part of the memory allocated by alloc_candev().
This patch moved the free it after last usage of priv.

While there convert all free_netdev() to free_candev() (which is currently
just a wrapper around free_netdev()) to be symetrically with the allocation
via alloc_candev().
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>