net/sched: sch_qfq: refactor parsing of netlink parameters

[ Upstream commit 25369891 ]

Two parameters can be transformed into netlink policies and
validated while parsing the netlink message.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 3e337087 ("net/sched: sch_qfq: account for stab overhead in qfq_enqueue")
Signed-off-by: Sasha Levin <sashal@kernel.org>