arcnet: provide a buffer big enough to actually receive packets

[ Upstream commit 108639aac35eb57f1d0e8333f5fc8c7ff68df938 ]

struct archdr is only big enough to hold the header of various types of
arcnet packets. So to provide enough space to hold the data read from
hardware provide a buffer large enough to hold a packet with maximal
size.

The problem was noticed by the stack protector which makes the kernel
oops.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>