test(manifest): relative address integration tests

* Add a memory region defined by `relative-address` to
  `partition_manifest_service_sp1.dts`

Change-Id: I33667b606dfb58fb4f5a2e9dc9703c8ce5af7a03
diff --git a/test/hftest/service_common.c b/test/hftest/service_common.c
index bf3464d..a429beb 100644
--- a/test/hftest/service_common.c
+++ b/test/hftest/service_common.c
@@ -106,9 +106,17 @@
 			EXPECT_TRUE(fdt_read_number(&ffa_node, "pages-count",
 						    &number));
 			cur_region->page_count = (uint32_t)number;
-			EXPECT_TRUE(fdt_read_number(&ffa_node, "base-address",
-						    &number));
-			cur_region->base_address = number;
+
+			if (!fdt_read_number(&ffa_node, "base-address",
+					     &cur_region->base_address)) {
+				EXPECT_TRUE(fdt_read_number(&ffa_node,
+							    "relative-address",
+							    &number));
+				cur_region->base_address =
+					ctx->partition_manifest.load_addr +
+					number;
+			}
+
 			EXPECT_TRUE(fdt_read_number(&ffa_node, "attributes",
 						    &number));
 			cur_region->attributes = (uint32_t)number;