net/ena: set IO ring size to valid value

net/ena: set IO ring size to valid value

IO rings were configured with the maximum allowed size for the Tx/Rx
rings. However, the application could decide to create smaller rings.

This patch is using value stored in the ring instead of the value from
the adapter which is indicating the maximum allowed value.

Fixes: df238f84c0a2 ("net/ena: recreate HW IO rings on start and stop")
Cc: stable@dpdk.org
Signed-off-by: Michal Krawczyk <mk@semihalf.com>
Reviewed-by: Igor Chauskin <igorch@amazon.com>
Reviewed-by: Guy Tzalik <gtzalik@amazon.com>