test: dm: core: Add a test case for driver marked with DM_FLAG_PRE_RELOC flag

Now that we fixed the pre-relocation driver binding for driver marked
with DM_FLAG_PRE_RELOC flag, add a test case to cover that scenario.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 57e0dd7..ffc93d0 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -186,6 +186,10 @@
 		compatible = "denx,u-boot-fdt-test";
 	};
 
+	h-test {
+		compatible = "denx,u-boot-fdt-test1";
+	};
+
 	clocks {
 		clk_fixed: clk-fixed {
 			compatible = "fixed-clock";