e1000: 3 new driver stats for managability testing

Add 3 extra packet redirect counters for tracking purposes to make sure
we can test that all packets arrive properly.

Originally from Jesse Brandeburg <jesse.brandeburg@intel.com>,
rewritten to use feature flags by me.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/e1000/e1000_hw.h b/drivers/net/e1000/e1000_hw.h
index 15b8625..d671058 100644
--- a/drivers/net/e1000/e1000_hw.h
+++ b/drivers/net/e1000/e1000_hw.h
@@ -1464,6 +1464,7 @@
 	boolean_t		bad_tx_carr_stats_fd;
 	boolean_t		has_manc2h;
 	boolean_t		rx_needs_kicking;
+	boolean_t		has_smbus;
 };