ethdev: remove forcing stopped state upon close

ethdev: remove forcing stopped state upon close

When closing a port, it is supposed to be already stopped,
and marked as such with "dev_started" state zeroed by the stop API.

Resetting "dev_started" before calling the driver close operation
was hiding the case of not properly stopped port being closed.
The flag "dev_started" is not changed anymore in "rte_eth_dev_close()".

In case the "dev_stop" function is called from "dev_close",
bypassing "rte_eth_dev_stop()" API,
the "dev_started" state must be explicitly reset in the PMD
in order to keep the same behaviour.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>