e1000e: fix IPMI traffic

Some users reported that they have machines with BMCs enabled that cannot
receive IPMI traffic after e1000e is loaded.
http://marc.info/?l=e1000-devel&m=121909039127414&w=2
http://marc.info/?l=e1000-devel&m=121365543823387&w=2

This fixes the issue if they load with the new parameter = 0 by disabling
crc stripping, but leaves the performance feature on for most users.
Based on work done by Hong Zhang.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/e1000e/e1000.h

@@ -299,6 +299,7 @@ struct e1000_adapter {
 	unsigned long led_status;
 
 	unsigned int flags;
+	unsigned int flags2;
 	struct work_struct downshift_task;
 	struct work_struct update_phy_task;
 };
@@ -306,6 +307,7 @@ struct e1000_adapter {
 struct e1000_info {
 	enum e1000_mac_type	mac;
 	unsigned int		flags;
+	unsigned int            flags2;
 	u32			pba;
 	s32			(*get_variants)(struct e1000_adapter *);
 	struct e1000_mac_operations *mac_ops;
@@ -347,6 +349,9 @@ struct e1000_info {
 #define FLAG_RX_RESTART_NOW               (1 << 30)
 #define FLAG_MSI_TEST_FAILED              (1 << 31)
 
+/* CRC Stripping defines */
+#define FLAG2_CRC_STRIPPING               (1 << 0)
+
 #define E1000_RX_DESC_PS(R, i)	    \
 	(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))
 #define E1000_GET_DESC(R, i, type)	(&(((struct type *)((R).desc))[i]))