binman: Correct an 'aot' typo

Fix this typo.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/bintool.py b/tools/binman/bintool.py
index f460243..bb22968 100644
--- a/tools/binman/bintool.py
+++ b/tools/binman/bintool.py
@@ -389,7 +389,7 @@
 
     @classmethod
     def apt_install(cls, package):
-        """Install a bintool using the 'aot' tool
+        """Install a bintool using the 'apt' tool
 
         This requires use of servo so may request a password