ARM: PXA: Z2: Keep kbd backlight disabled by default

It eats too much power, and anyway it's not usefull
during boot process. Userspace can enable it later.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
diff --git a/arch/arm/mach-pxa/z2.c b/arch/arm/mach-pxa/z2.c
index 4df1ecb..9b6ab07 100644
--- a/arch/arm/mach-pxa/z2.c
+++ b/arch/arm/mach-pxa/z2.c
@@ -204,7 +204,7 @@
 		/* Keypad Backlight */
 		.pwm_id		= 1,
 		.max_brightness	= 1023,
-		.dft_brightness	= 512,
+		.dft_brightness	= 0,
 		.pwm_period_ns	= 1260320,
 	},
 	[1] = {