idt77252 is broken and wont load on amd64 systems
modprobe idt77252 shows the following
idt77252_init: skb->cb is too small (48 < 56)
Add packed attribute to struct idt77252_skb_prv and struct atm_skb_data
so that the total size can be <= sizeof(skb->cb)
Also convert runtime size check to buildtime size check in
idt77252_init()
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>