net: ena: avoid memory access violation by validating req_id properly

Rx req_id is an index in struct ena_eth_io_rx_cdesc_base.
The driver should validate that the Rx req_id it received from
the device is in range [0, ring_size -1].  Failure to do so could
yield to potential memory access violoation.
The validation was mistakenly done when refilling
the Rx submission queue and not in Rx completion queue.

Fixes: ad974bae

 ("net: ena: add support for out of order rx buffers refill")
Signed-off-by: Noam Dagan <ndagan@amazon.com>
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>