[ARM] pxa: update pwm_backlight->notify() to include missed 'struct device *'

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/palmtx.c b/arch/arm/mach-pxa/palmtx.c
index 7bf18c2..b37a025 100644
--- a/arch/arm/mach-pxa/palmtx.c
+++ b/arch/arm/mach-pxa/palmtx.c
@@ -269,7 +269,7 @@
 	return ret;
 }
 
-static int palmtx_backlight_notify(int brightness)
+static int palmtx_backlight_notify(struct device *dev, int brightness)
 {
 	gpio_set_value(GPIO_NR_PALMTX_BL_POWER, brightness);
 	gpio_set_value(GPIO_NR_PALMTX_LCD_POWER, brightness);