device_tree.c: Don't use load_image()

The load_image() function is deprecated, as it does not let the
caller specify how large the buffer to read the file into is.
Instead use load_image_size().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20181130151712.2312-9-peter.maydell@linaro.org
(cherry picked from commit da885fe)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

device_tree.c

@@ -91,7 +91,7 @@ void *load_device_tree(const char *filename_path, int *sizep)
     /* First allocate space in qemu for device tree */
     fdt = g_malloc0(dt_size);
 
-    dt_file_load_size = load_image(filename_path, fdt);
+    dt_file_load_size = load_image_size(filename_path, fdt, dt_size);
     if (dt_file_load_size < 0) {
         error_report("Unable to open device tree file '%s'",
                      filename_path);