ixgbe: check for WoL support in single function

This patch consolidates the case logic for checking whether a device supports
WoL into a single place. Previously ethtool and probe used similar logic that
was copied and maintained separately. This patch encapsulates the core logic
into a function so that a user only has to update one place.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index 74e1921..8e082f2 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -600,6 +600,8 @@
 				   struct ixgbe_ring *);
 extern void ixgbe_update_stats(struct ixgbe_adapter *adapter);
 extern int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter);
+extern int ixgbe_wol_supported(struct ixgbe_adapter *adapter, u16 device_id,
+			       u16 subdevice_id);
 extern void ixgbe_clear_interrupt_scheme(struct ixgbe_adapter *adapter);
 extern netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *,
 					 struct ixgbe_adapter *,