igb: make local functions static

Sparse caught two functions that were only being used in one file.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/intel/igb/e1000_mac.c b/drivers/net/ethernet/intel/igb/e1000_mac.c
index 73aac08..36450d3 100644
--- a/drivers/net/ethernet/intel/igb/e1000_mac.c
+++ b/drivers/net/ethernet/intel/igb/e1000_mac.c
@@ -151,7 +151,7 @@
  *  Writes value at the given offset in the register array which stores
  *  the VLAN filter table.
  **/
-void igb_write_vfta_i350(struct e1000_hw *hw, u32 offset, u32 value)
+static void igb_write_vfta_i350(struct e1000_hw *hw, u32 offset, u32 value)
 {
 	int i;