ARM: dts: atlas7: put pinctl property to get pinmux for NAND

Nand controller often share some pins with sd/mmc controller on
atlas and prima series, nand node can be disabled if the pins are
used by sd/mmc controller.
Signed-off-by: Huayi Li <huayi.li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>

arch/arm/boot/dts/atlas7.dtsi

@@ -1458,6 +1458,8 @@ gpio_0: gpio_mediam@17040000 {
 			nand@17050000 {
 				compatible = "sirf,atlas7-nand";
 				reg = <0x17050000 0x10000>;
+				pinctrl-names = "default";
+				pinctrl-0 = <&nd_df_pmx>;
 				interrupts = <0 41 0>;
 				clocks = <&car 108>, <&car 112>;
 				clock-names = "nand_io", "nand_nand";