ethdev: remove experimental flag of ports enumeration

ethdev: remove experimental flag of ports enumeration

The basic operations for ports enumeration should not be
considered as experimental in DPDK 18.05.

The iterator RTE_ETH_FOREACH_DEV was introduced in DPDK 17.05.
It uses the function the rte_eth_find_next_owned_by() to get
only ownerless ports. Its API can be considered stable.
So the flag experimental is removed from rte_eth_find_next_owned_by().

The flag experimental is removed from rte_eth_dev_count_avail()
which is the new name of the old function rte_eth_dev_count().

The flag experimental is set to rte_eth_dev_count_total()
in the .c file for consistency with the declaration in the .h file.

A lot of internal applications are fixed to not allow experimental API.

Fixes: 8728ccf37615 ("fix ethdev ports enumeration")
Fixes: d9a42a69febf ("ethdev: deprecate port count function")
Fixes: e70e26861eaf ("net/mvpp2: fix build")
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Tested-by: David Marchand <david.marchand@6wind.com>