ARM: socfpga: Make DRAM node available in SPL

The SPL can also parse the DRAM configuration node to figure out the
memory layout, make sure it is available.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Chin Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>

arch/arm/dts/socfpga_arria10_socdk.dtsi

@@ -34,6 +34,7 @@
 		name = "memory";
 		device_type = "memory";
 		reg = <0x0 0x40000000>; /* 1GB */
+		u-boot,dm-pre-reloc;
 	};
 
 	a10leds {