rtl8180: add parentheses to REG_ADDR macros

Parentheses are missing around the macro argument, causing the
macro possibly not to work passing certain expressions as
arguments.

This should not cause any issues with current code, however it's
worth to add them, as a good practice, and to eventually avoid
future bugs.
Suggested-by: Dave Kilroy <kilroyd@googlemail.com>
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl818x.h

@@ -334,9 +334,9 @@ struct rtl818x_csr {
  * I don't like to introduce a ton of "reserved"..
  * They are for RTL8187SE
  */
-#define REG_ADDR1(addr)	((u8 __iomem *)priv->map + addr)
-#define REG_ADDR2(addr)	((__le16 __iomem *)priv->map + (addr >> 1))
-#define REG_ADDR4(addr)	((__le32 __iomem *)priv->map + (addr >> 2))
+#define REG_ADDR1(addr)	((u8 __iomem *)priv->map + (addr))
+#define REG_ADDR2(addr)	((__le16 __iomem *)priv->map + ((addr) >> 1))
+#define REG_ADDR4(addr)	((__le32 __iomem *)priv->map + ((addr) >> 2))
 
 #define FEMR_SE		REG_ADDR2(0x1D4)
 #define ARFR		REG_ADDR2(0x1E0)