ARM: dts: socfpga: remove 'num-slots' property for dwmmc

Since 'num-slots' had already deprecated, remove the property in
device-tree file.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

arch/arm/boot/dts/socfpga_arria10_socdk_sdmmc.dts

@@ -20,7 +20,6 @@
 
 &mmc {
 	status = "okay";
-	num-slots = <1>;
 	cap-sd-highspeed;
 	broken-cd;
 	bus-width = <4>;

arch/arm/boot/dts/socfpga_arria5.dtsi

@@ -30,7 +30,6 @@ osc1 {
 		};
 
 		mmc0: dwmmc0@ff704000 {
-			num-slots = <1>;
 			broken-cd;
 			bus-width = <4>;
 			cap-mmc-highspeed;

arch/arm/boot/dts/socfpga_cyclone5.dtsi

@@ -31,7 +31,6 @@ osc1 {
 		};
 
 		mmc0: dwmmc0@ff704000 {
-			num-slots = <1>;
 			broken-cd;
 			bus-width = <4>;
 			cap-mmc-highspeed;

arch/arm/boot/dts/socfpga_vt.dts

@@ -42,7 +42,6 @@ osc1 {
 		};
 
 		dwmmc0@ff704000 {
-			num-slots = <1>;
 			broken-cd;
 			bus-width = <4>;
 			cap-mmc-highspeed;