igb: fix static function warnings reported by sparse

igb_update/validate_nvm_checksum_with_offset() should be static.
Also removes unneeded prototypes for the above functions.
Signed-off-by: NEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: NAaron Brown  <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/e1000_82575.c

@@ -66,10 +66,6 @@ static s32  igb_set_pcie_completion_timeout(struct e1000_hw *hw);
 static s32  igb_reset_mdicnfg_82580(struct e1000_hw *hw);
 static s32  igb_validate_nvm_checksum_82580(struct e1000_hw *hw);
 static s32  igb_update_nvm_checksum_82580(struct e1000_hw *hw);
-static s32  igb_update_nvm_checksum_with_offset(struct e1000_hw *hw,
-						u16 offset);
-static s32 igb_validate_nvm_checksum_with_offset(struct e1000_hw *hw,
-						u16 offset);
 static s32 igb_validate_nvm_checksum_i350(struct e1000_hw *hw);
 static s32 igb_update_nvm_checksum_i350(struct e1000_hw *hw);
 static const u16 e1000_82580_rxpbs_table[] =
@@ -1820,7 +1816,8 @@ u16 igb_rxpbs_adjust_82580(u32 data)
  *  Calculates the EEPROM checksum by reading/adding each word of the EEPROM
  *  and then verifies that the sum of the EEPROM is equal to 0xBABA.
  **/
-s32 igb_validate_nvm_checksum_with_offset(struct e1000_hw *hw, u16 offset)
+static s32 igb_validate_nvm_checksum_with_offset(struct e1000_hw *hw,
+						 u16 offset)
 {
 	s32 ret_val = 0;
 	u16 checksum = 0;
@@ -1855,7 +1852,7 @@ s32 igb_validate_nvm_checksum_with_offset(struct e1000_hw *hw, u16 offset)
  *  up to the checksum.  Then calculates the EEPROM checksum and writes the
  *  value to the EEPROM.
  **/
-s32 igb_update_nvm_checksum_with_offset(struct e1000_hw *hw, u16 offset)
+static s32 igb_update_nvm_checksum_with_offset(struct e1000_hw *hw, u16 offset)
 {
 	s32 ret_val;
 	u16 checksum = 0;