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: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index 323cb14..a8b99ba 100644
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -1916,7 +1916,7 @@
 
 	phy->cable_length = (phy->min_cable_length + phy->max_cable_length) / 2;
 
-	return ret_val;
+	return 0;
 }
 
 /**