fromupstream: Give help if no arguments

If you just run "fromupstream.py" you want some help.

BUG=None
TEST=Run w/ no args

Change-Id: I7e0f7ea400e1ef538dc9dc04f85aad783a7d1155
Reviewed-on: https://chromium-review.googlesource.com/1045504
Commit-Ready: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
diff --git a/contrib/fromupstream.py b/contrib/fromupstream.py
index 7f21f5d..42b6ad2 100755
--- a/contrib/fromupstream.py
+++ b/contrib/fromupstream.py
@@ -103,7 +103,7 @@
                         help='Overrides the source line, last line, ex: ' +
                         '(am from http://....)')
     parser.add_argument('locations',
-                        nargs='*',
+                        nargs='+',
                         help='Patchwork url (either ' +
                         'https://patchwork.kernel.org/patch/###/ or ' +
                         'pw://###), linux commit like linux://HASH, git ' +