fdt: Correct warning in fdt_setup_simplefb_node()

Adjust the printf() string to avoid a warning on sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/fdt_support.c

@@ -1533,7 +1533,7 @@ int fdt_setup_simplefb_node(void *fdt, int node, u64 base_address, u32 width,
 	if (ret < 0)
 		return ret;
 
-	snprintf(name, sizeof(name), "framebuffer@%llx", base_address);
+	snprintf(name, sizeof(name), "framebuffer@%" PRIx64, base_address);
 	ret = fdt_set_name(fdt, node, name);
 	if (ret < 0)
 		return ret;