[ARM] pxa/spitz: fix On/off key name to fix warning during boot

On/Off contains slash in the name, which causes warning during boot.
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NEric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/spitz.c

@@ -363,7 +363,7 @@ static struct gpio_keys_button spitz_gpio_keys[] = {
 		.type	= EV_PWR,
 		.code	= KEY_SUSPEND,
 		.gpio	= SPITZ_GPIO_ON_KEY,
-		.desc	= "On/Off",
+		.desc	= "On Off",
 		.wakeup	= 1,
 	},
 	/* Two buttons detecting the lid state */