net: ena: add ethtool function for changing io queue sizes

Implement the set_ringparam() function of the ethtool interface
to enable the changing of io queue sizes.

Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>