sandbox: Initialize sysreset before relocation

Without this the early sysreset code cannot be tested.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/dts/sandbox.dtsi b/arch/sandbox/dts/sandbox.dtsi
index d2db1ea..7387b54 100644
--- a/arch/sandbox/dts/sandbox.dtsi
+++ b/arch/sandbox/dts/sandbox.dtsi
@@ -239,6 +239,7 @@
 
 	reset@1 {
 		compatible = "sandbox,reset";
+		u-boot,dm-pre-proper;
 	};
 
 	rng {
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index b853e13..70e27cd 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -1125,10 +1125,12 @@
 
 	reset@0 {
 		compatible = "sandbox,warm-reset";
+		u-boot,dm-pre-proper;
 	};
 
 	reset@1 {
 		compatible = "sandbox,reset";
+		u-boot,dm-pre-proper;
 	};
 
 	resetc: reset-ctl {