ARM: dts: Add disable-wp for sd card slot on smdk5250

The next change will remove the code from the dw_mmc-exynos that added
the DW_MCI_QUIRK_NO_WRITE_PROTECT.  Keep existing functionality of
having no write protect pin on smdk5250 by adding the disable-wp
property.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Seungwon Jeon <tgih.jun@samsung.com>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Chris Ball <cjb@laptop.org>

arch/arm/boot/dts/exynos5250-smdk5250.dts

@@ -146,6 +146,7 @@ slot@0 {
 			reg = <0>;
 			bus-width = <4>;
 			samsung,cd-pinmux-gpio = <&gpc3 2 2 3 3>;
+			disable-wp;
 			gpios = <&gpc3 0 2 0 3>, <&gpc3 1 2 0 3>,
 				<&gpc3 3 2 3 3>, <&gpc3 4 2 3 3>,
 				<&gpc3 5 2 3 3>, <&gpc3 6 2 3 3>,