gpio: twl6040: Use bitops

It's nice to use BIT() macros rather than open coding the same.
It's good practice as sometimes people use BIT(31) and forget
that the constant must be cast unsigned long.
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-twl6040.c

@@ -15,6 +15,7 @@
 #include <linux/irq.h>
 #include <linux/gpio/driver.h>
 #include <linux/platform_device.h>
+#include <linux/bitops.h>
 #include <linux/of.h>
 
 #include <linux/mfd/twl6040.h>
@@ -28,7 +29,7 @@ static int twl6040gpo_get(struct gpio_chip *chip, unsigned offset)
 	if (ret < 0)
 		return ret;
 
-	return (ret >> offset) & 1;
+	return !!(ret & BIT(offset));
 }
 
 static int twl6040gpo_direction_out(struct gpio_chip *chip, unsigned offset,
@@ -49,9 +50,9 @@ static void twl6040gpo_set(struct gpio_chip *chip, unsigned offset, int value)
 		return;
 
 	if (value)
-		gpoctl = ret | (1 << offset);
+		gpoctl = ret | BIT(offset);
 	else
-		gpoctl = ret & ~(1 << offset);
+		gpoctl = ret & ~BIT(offset);
 
 	twl6040_reg_write(twl6040, TWL6040_REG_GPOCTL, gpoctl);
 }