sandbox: Fix set_working_fdt_addr users

When running sandbox with the new pointer sanitization we just recently
introduced, we're running into a case with FIT images where we end up
interpreting pointers as addresses.

What happened is that most callers of set_working_fdt_addr() simply
convert pointers into addresses without taking into account that they
might be 2 separate address spaces. Fix the callers up to map their
pointers into addresses.

This makes sandbox tests pass for me again.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/common/bootm.c b/common/bootm.c
index e517d9f..8bf84eb 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -262,7 +262,7 @@
 		puts("Could not find a valid device tree\n");
 		return 1;
 	}
-	set_working_fdt_addr((ulong)images.ft_addr);
+	set_working_fdt_addr(map_to_sysmem(images.ft_addr));
 #endif
 
 #if IMAGE_ENABLE_FIT