binman: Support alignment of files

When packing files it is sometimes useful to align the start of each file,
e.g. if the flash driver can only access 32-bit-aligned data. Provides a
new property to support this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/state.py b/tools/binman/state.py
index 36bc513..bb3e36e 100644
--- a/tools/binman/state.py
+++ b/tools/binman/state.py
@@ -314,6 +314,16 @@
     for n in GetUpdateNodes(node):
         n.AddString(prop, value)
 
+def AddInt(node, prop, value):
+    """Add a new string property to affected device trees
+
+    Args:
+        prop_name: Name of property
+        val: Integer value of property
+    """
+    for n in GetUpdateNodes(node):
+        n.AddInt(prop, value)
+
 def SetInt(node, prop, value, for_repack=False):
     """Update an integer property in affected device trees with an integer value