binman: Collect the version number for mkeficapsule

Now that this tool has a version number, collect it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/btool/mkeficapsule.py b/tools/binman/btool/mkeficapsule.py
index ef1da63..f7e5a88 100644
--- a/tools/binman/btool/mkeficapsule.py
+++ b/tools/binman/btool/mkeficapsule.py
@@ -33,7 +33,8 @@
     commandline, or through a config file.
     """
     def __init__(self, name):
-        super().__init__(name, 'mkeficapsule tool for generating capsules')
+        super().__init__(name, 'mkeficapsule tool for generating capsules',
+                         r'mkeficapsule version (.*)')
 
     def generate_capsule(self, image_index, image_guid, hardware_instance,
                          payload, output_fname, priv_key, pub_key,