e1000: workaround for the ESB2 NIC RX unit issue

In rare occasions, ESB2 systems would end up started without the RX
unit being turned on. Add a check that runs post-init to work around
this issue.

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.c b/drivers/net/e1000/e1000_hw.c
index 1ea556e..ea7b371 100644
--- a/drivers/net/e1000/e1000_hw.c
+++ b/drivers/net/e1000/e1000_hw.c
@@ -452,6 +452,12 @@
 	if (hw->mac_type >= e1000_82571)
 		hw->has_manc2h = TRUE;
 
+	/* In rare occasions, ESB2 systems would end up started without
+	 * the RX unit being turned on.
+	 */
+	if (hw->mac_type == e1000_80003es2lan)
+		hw->rx_needs_kicking = TRUE;
+
 	return E1000_SUCCESS;
 }