e1000e: resolve checkpatch JIFFIES_COMPARISON warning

WARNING:JIFFIES_COMPARISON: Comparing jiffies is almost always wrong;
prefer time_after, time_before and friends
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/ethtool.c

@@ -1665,7 +1665,7 @@ static int e1000_run_loopback_test(struct e1000_adapter *adapter)
 			ret_val = 13;	/* ret_val is the same as mis-compare */
 			break;
 		}
-		if (jiffies >= (time + 20)) {
+		if (time_after(jiffies, time + 20)) {
 			ret_val = 14;	/* error code for time out error */
 			break;
 		}