ARM: dts: uniphier: add u-boot, dm-pre-reloc to use eMMC boot on sLD3

The eMMC on sLD3 is assigned with dedicated pins (only multiplexed
with GPIO), so it shouldn't hurt to enable eMMC on SPL all the time.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/uniphier-ph1-sld3.dtsi b/arch/arm/dts/uniphier-ph1-sld3.dtsi
index c3adaf1..6a95541 100644
--- a/arch/arm/dts/uniphier-ph1-sld3.dtsi
+++ b/arch/arm/dts/uniphier-ph1-sld3.dtsi
@@ -61,6 +61,7 @@
 		#size-cells = <1>;
 		ranges;
 		interrupt-parent = <&intc>;
+		u-boot,dm-pre-reloc;
 
 		timer@20000200 {
 			compatible = "arm,cortex-a9-global-timer";