ixgbe: cleanup make ixgbe_set_ethertype_anti_spoofing_X550 static

Correcting a mistake when I initial created this function.  I should
have made this static since it is only referenced where the function
pointer is assigned.

CC: <kernel-team@fb.com>
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c

@@ -1347,8 +1347,8 @@ static s32 ixgbe_reset_hw_X550em(struct ixgbe_hw *hw)
  *  @enable: enable or disable switch for Ethertype anti-spoofing
  *  @vf: Virtual Function pool - VF Pool to set for Ethertype anti-spoofing
  **/
-void ixgbe_set_ethertype_anti_spoofing_X550(struct ixgbe_hw *hw, bool enable,
-					    int vf)
+static void ixgbe_set_ethertype_anti_spoofing_X550(struct ixgbe_hw *hw,
+						   bool enable, int vf)
 {
 	int vf_target_reg = vf >> 3;
 	int vf_target_shift = vf % 8 + IXGBE_SPOOF_ETHERTYPEAS_SHIFT;