net/sched: taprio: Fix init procedure

net/sched: taprio: Fix init procedure

Commit ab26e58e9fe28c ("net: taprio offload: enforce qdisc to netdev queue mapping")
resulted in duplicate entries in the qdisc hash.
While this did not impact the overall operation of the qdisc and taprio
code paths, it did result in an infinite loop when dumping the qdisc
properties, at least on one target (NXP LS1028 ARDB).
Removing the duplicate call to qdisc_hash_add() solves the problem.

Fixes: ab26e58e9fe28c ("net: taprio offload: enforce qdisc to netdev queue mapping")
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>