binman: cbfs: Fix IFWI typo

This comment references the wrong thing. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/tools/binman/etype/cbfs.py b/tools/binman/etype/cbfs.py
index e9aed83..744a32f 100644
--- a/tools/binman/etype/cbfs.py
+++ b/tools/binman/etype/cbfs.py
@@ -204,7 +204,7 @@
         return True
 
     def _ReadSubnodes(self):
-        """Read the subnodes to find out what should go in this IFWI"""
+        """Read the subnodes to find out what should go in this CBFS"""
         for node in self._node.subnodes:
             entry = Entry.Create(self, node)
             entry.ReadNode()