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>
diff --git a/arch/arm/mach-msm/board-trout-gpio.c b/arch/arm/mach-msm/board-trout-gpio.c
index a604ec1..31117a4 100644
--- a/arch/arm/mach-msm/board-trout-gpio.c
+++ b/arch/arm/mach-msm/board-trout-gpio.c
@@ -74,8 +74,6 @@
 
 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);
 }