UPSTREAM: net: sched: sch_multiq: fix possible OOB write in multiq_tune()

[ Upstream commit affc18fdc694190ca7575b9a86632a73b9fe043d ]

q->bands will be assigned to qopt->bands to execute subsequent code logic
after kmalloc. So the old q->bands should not be used in kmalloc.
Otherwise, an out-of-bounds write will occur.

Bug: 349777785
Fixes: c2999f7f ("net: sched: multiq: don't call qdisc_put() while holding tree lock")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Acked-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 0f208fad86631e005754606c3ec80c0d44a11882)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Iec8413c39878596795420ae58bbe6974890cf2de