binman: Obtain the list of device trees from the config

We always have a device tree for U-Boot proper. But we may also have one
for SPL and TPL. Add a new Entry method to find out what DTs an entry
has, and use that list when updating DTs.

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

tools/binman/control.py

@@ -137,7 +137,7 @@ def Binman(options, args):
                 if skip:
                     print 'Skipping images: %s\n' % ', '.join(skip)
 
-            state.Prepare(dtb)
+            state.Prepare(images, dtb)
 
             # Prepare the device tree by making sure that any missing
             # properties are added (e.g. 'pos' and 'size'). The values of these