net: ena: ethtool: remove redundant non-zero check on rc

The non-zero check on rc is redundant as a previous non-zero
check on rc will always return and the second check is never
reached, hence it is redundant and can be removed.  Also
remove a blank line.

Addresses-Coverity: ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>