e1000e: cleanup functions that clear hardware statistics

The e1000_clear_hw_cntrs_*() functions read the registers to clear them.
There is no reason to save the register contents so the temp variable can
be removed.

Signed-off-by: Bruce Allan <bruce.w.allan@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/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index f8ee0f2..2c1d08e 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -3402,24 +3402,23 @@
  **/
 static void e1000_clear_hw_cntrs_ich8lan(struct e1000_hw *hw)
 {
-	u32 temp;
 	u16 phy_data;
 
 	e1000e_clear_hw_cntrs_base(hw);
 
-	temp = er32(ALGNERRC);
-	temp = er32(RXERRC);
-	temp = er32(TNCRS);
-	temp = er32(CEXTERR);
-	temp = er32(TSCTC);
-	temp = er32(TSCTFC);
+	er32(ALGNERRC);
+	er32(RXERRC);
+	er32(TNCRS);
+	er32(CEXTERR);
+	er32(TSCTC);
+	er32(TSCTFC);
 
-	temp = er32(MGTPRC);
-	temp = er32(MGTPDC);
-	temp = er32(MGTPTC);
+	er32(MGTPRC);
+	er32(MGTPDC);
+	er32(MGTPTC);
 
-	temp = er32(IAC);
-	temp = er32(ICRXOC);
+	er32(IAC);
+	er32(ICRXOC);
 
 	/* Clear PHY statistics registers */
 	if ((hw->phy.type == e1000_phy_82578) ||