e1000e: fix error checks

Spotted by the Coverity checker.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/e1000e/ethtool.c

@@ -1451,11 +1451,11 @@ static int e1000_loopback_test(struct e1000_adapter *adapter, u64 *data)
 	}
 
 	*data = e1000_setup_desc_rings(adapter);
-	if (data)
+	if (*data)
 		goto out;
 
 	*data = e1000_setup_loopback_test(adapter);
-	if (data)
+	if (*data)
 		goto err_loopback;
 
 	*data = e1000_run_loopback_test(adapter);