patman: Add project-default for 'gcc'

Add defaults for FSF/GNU projects, such as gcc, that provide sensible
settings for those projects.

Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/settings.py b/tools/patman/settings.py
index 60cdc1c..13c1ee4 100644
--- a/tools/patman/settings.py
+++ b/tools/patman/settings.py
@@ -23,7 +23,12 @@
     "u-boot": {},
     "linux": {
         "process_tags": "False",
-    }
+    },
+    "gcc": {
+        "process_tags": "False",
+        "add_signoff": "False",
+        "check_patch": "False",
+    },
 }
 
 class _ProjectConfigParser(ConfigParser.SafeConfigParser):