ionic: drop ethtool driver version

Use the default kernel version in ethtool drv_info output
and drop the module version.

Cc: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>