ethdev: clarify device queue state after start and stop

Drivers start/stop device queues on port start/stop, but not all drivers
update queue state accordingly.

This becomes more visible if a speci

ethdev: clarify device queue state after start and stop

Drivers start/stop device queues on port start/stop, but not all drivers
update queue state accordingly.

This becomes more visible if a specific queue stopped explicitly and
port stopped/started later, in this case although all queues are
started, the state of that specific queue is stopped and it is
misleading.

Misrepresentation of queue state became a defect with commit [1] that
does forwarding decision based on queue state and commit [2] that gets
up to date queue state from ethdev/device before forwarding.

[1]
commit 3c4426db54fc ("app/testpmd: do not poll stopped queues")

[2]
commit 5028f207a4fa ("app/testpmd: fix secondary process packet forwarding")

This patch documents that status of all queues of a device should be
`RTE_ETH_QUEUE_STATE_STOPPED` after port stop and their status should
be`RTE_ETH_QUEUE_STATE_STARTED` after port start.

Also an unit test added to verify drivers.

Signed-off-by: Ferruh Yigit <ferruh.yigit@amd.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>

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