ARM: pxa: Properly configure PWM period for palm27x

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/palm27x.c

@@ -323,7 +323,7 @@ static struct platform_pwm_backlight_data palm27x_backlight_data = {
 	.pwm_id		= 0,
 	.max_brightness	= 0xfe,
 	.dft_brightness	= 0x7e,
-	.pwm_period_ns	= 3500,
+	.pwm_period_ns	= 3500 * 1024,
 	.init		= palm27x_backlight_init,
 	.notify		= palm27x_backlight_notify,
 	.exit		= palm27x_backlight_exit,