doc: announce ethdev API change for preferred burst size

doc: announce ethdev API change for preferred burst size

rte_eth_rx_burst(..,nb_pkts) function has semantic that if return value
is smaller than requested, application can consider it end of packet
stream. Some hardware can only support smaller burst sizes which need
to be advertised. Similar is the case for Tx burst.

This patch adds deprecation notice for rte_eth_dev_info structure as
new members, for preferred Rx and Tx burst and ring size would be
added - impacting the size of the structure.

Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Zhiyong Yang <zhiyong.yang@intel.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>