dtoc: Fix bug in GetProp()

This does not actually call fdtget correctly when requesting a particular
type. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/dtoc/fdt_fallback.py b/tools/dtoc/fdt_fallback.py
index 0c0ebbc..7d52da7 100644
--- a/tools/dtoc/fdt_fallback.py
+++ b/tools/dtoc/fdt_fallback.py
@@ -160,7 +160,7 @@
         if default is not None:
           args += ['-d', str(default)]
         if typespec is not None:
-          args += ['-t%s' % typespec]
+          args += ['-t', typespec]
         out = command.Output('fdtget', *args)
         return out.strip()