kernel: drivers: igb: use READ_ONCE instead of ACCESS_ONCE

ACCESS_ONCE isn't available starting from kernel v4.15.
Signed-off-by: Roman Stratiienko <roman.stratiienko@globallogic.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kernel/drivers/net/drivers/igb/e1000_regs.h

@@ -372,7 +372,7 @@ u32 igb_rd32(struct e1000_hw *hw, u32 reg);
 /* write operations, indexed using DWORDS */
 #define wr32(reg, val) \
 do { \
-	u8 __iomem *hw_addr = ACCESS_ONCE((hw)->hw_addr); \
+	u8 __iomem *hw_addr = READ_ONCE((hw)->hw_addr); \
 	if (!E1000_REMOVED(hw_addr)) \
 		writel((val), &hw_addr[(reg)]); \
 } while (0)

kernel/drivers/net/drivers/igb/igb_main.c

@@ -654,7 +654,7 @@ static void igb_cache_ring_register(struct igb_adapter *adapter)
 u32 igb_rd32(struct e1000_hw *hw, u32 reg)
 {
 	struct igb_adapter *igb = container_of(hw, struct igb_adapter, hw);
-	u8 __iomem *hw_addr = ACCESS_ONCE(hw->hw_addr);
+	u8 __iomem *hw_addr = READ_ONCE(hw->hw_addr);
 	u32 value = 0;
 
 	if (E1000_REMOVED(hw_addr))