rtl8180: silence "dubious: x | !y" sparse warning

  CHECK   drivers/net/wireless/rtl818x/rtl8180_rtl8225.c
drivers/net/wireless/rtl818x/rtl8180_rtl8225.c:53:33: warning: dubious: x | !y

The existing code is clever and works fine, but it's not worth even a
single line of Sparse warning SPAM...
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180_rtl8225.c

@@ -50,7 +50,10 @@ static void rtl8225_write(struct ieee80211_hw *dev, u8 addr, u16 data)
 	udelay(10);
 
 	for (i = 15; i >= 0; i--) {
-		u16 reg = reg80 | !!(bangdata & (1 << i));
+		u16 reg = reg80;
+
+		if (bangdata & (1 << i))
+			reg |= 1;
 
 		if (i & 1)
 			rtl818x_iowrite16(priv, &priv->map->RFPinsOutput, reg);