ARM: zynq: Enable u-boot,dm-pre-reloc for sdhci

Enable u-boot,dm-pre-reloc for sdhci for zc706, zed and zybo.
And create aliases for it.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/dts/zynq-zybo.dts b/arch/arm/dts/zynq-zybo.dts
index dcfc00e..199264a 100644
--- a/arch/arm/dts/zynq-zybo.dts
+++ b/arch/arm/dts/zynq-zybo.dts
@@ -16,6 +16,7 @@
 	aliases {
 		ethernet0 = &gem0;
 		serial0 = &uart1;
+		mmc0 = &sdhci0;
 	};
 
 	memory {
@@ -45,6 +46,7 @@
 };
 
 &sdhci0 {
+	u-boot,dm-pre-reloc;
 	status = "okay";
 };