msm: Warning fix in trout gpio board file

arch/arm/mach-msm/board-trout-gpio.c: In function 'trout_gpio_to_irq':
arch/arm/mach-msm/board-trout-gpio.c:77: error: unused variable 'msm_gpio'
Signed-off-by: David Brown <davidb@codeaurora.org>

arch/arm/mach-msm/board-trout-gpio.c

@@ -74,8 +74,6 @@ static int msm_gpiolib_direction_output(struct gpio_chip *chip,
 
 static int trout_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 {
-	struct msm_gpio_chip *msm_gpio = to_msm_gpio_chip(chip);
-
 	return TROUT_GPIO_TO_INT(offset + chip->base);
 }