e1000e: cleanup: always return 0

These are a few instances of returning a value that can only be 0 so just
use a 'return 0' to make it more obvious.
Signed-off-by: NBruce Allan <bruce.w.allan@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/e1000e/82571.c

@@ -796,7 +796,7 @@ static s32 e1000_update_nvm_checksum_82571(struct e1000_hw *hw)
 	 * otherwise, commit the checksum to the flash NVM.
 	 */
 	if (hw->nvm.type != e1000_nvm_flash_hw)
-		return ret_val;
+		return 0;
 
 	/* Check for pending operations. */
 	for (i = 0; i < E1000_FLASH_UPDATES; i++) {

drivers/net/ethernet/intel/e1000e/ich8lan.c

@@ -1948,7 +1948,7 @@ static s32 e1000_set_d0_lplu_state_ich8lan(struct e1000_hw *hw, bool active)
 	u16 data;
 
 	if (phy->type == e1000_phy_ife)
-		return ret_val;
+		return 0;
 
 	phy_ctrl = er32(PHY_CTRL);
 

drivers/net/ethernet/intel/e1000e/mac.c

@@ -444,7 +444,7 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
 		return ret_val;
 
 	if (!link)
-		return ret_val;	/* No link detected */
+		return 0;	/* No link detected */
 
 	mac->get_link_status = false;
 

drivers/net/ethernet/intel/e1000e/phy.c

@@ -1916,7 +1916,7 @@ s32 e1000e_get_cable_length_igp_2(struct e1000_hw *hw)
 
 	phy->cable_length = (phy->min_cable_length + phy->max_cable_length) / 2;
 
-	return ret_val;
+	return 0;
 }
 
 /**