net: ena: Remove unused code

The ENA_DEFAULT_MIN_RX_BUFF_ALLOC_SIZE macro,
ena_xdp_queues_present() function and SUSPEND_RESUME enums aren't used
in the driver, and so not needed.

Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: Shay Agroskin <shayagr@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>