ethdev: add device flag to bypass auto-filled queue xstats

ethdev: add device flag to bypass auto-filled queue xstats

Queue stats are stored in 'struct rte_eth_stats' as array and array size
is defined by 'RTE_ETHDEV_QUEUE_STAT_CNTRS' compile time flag.

As a result of technical board discussion, decided to remove the queue
statistics from 'struct rte_eth_stats' in the long term.

Instead PMDs should represent the queue statistics via xstats, this
gives more flexibility on the number of the queues supported.

Currently queue stats in the xstats are filled by ethdev layer, using
some basic stats, when queue stats removed from basic stats the
responsibility to fill the relevant xstats will be pushed to the PMDs.

During the switch period, temporary 'RTE_ETH_DEV_AUTOFILL_QUEUE_XSTATS'
device flag is created. Initially all PMDs using xstats set this flag.
The PMDs implemented queue stats in the xstats should clear the flag.

When all PMDs switch to the xstats for the queue stats, queue stats
related fields from 'struct rte_eth_stats' will be removed, as well as
'RTE_ETH_DEV_AUTOFILL_QUEUE_XSTATS' flag.
Later 'RTE_ETHDEV_QUEUE_STAT_CNTRS' compile time flag also can be
removed.

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Haiyue Wang <haiyue.wang@intel.com>
Acked-by: Xiao Wang <xiao.w.wang@intel.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>