net: sched: cbq: create block for q->link.block

net: sched: cbq: create block for q->link.block

q->link.block is not initialized, that leads to EINVAL when one tries to
add filter there. So initialize it properly.

This can be reproduced by:
$ tc qdisc add dev eth0 root handle 1: cbq avpkt 1000 rate 1000Mbit bandwidth 1000Mbit
$ tc filter add dev eth0 parent 1: protocol ip prio 100 u32 match ip protocol 0 0x00 flowid 1:1

Reported-by: Jaroslav Aster <[email protected]>
Reported-by: Ivan Vecera <[email protected]>
Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Eelco Chaudron <[email protected]>
Reviewed-by: Ivan Vecera <[email protected]>
Signed-off-by: David S. Miller <[email protected]>