Merge pull request #741 from sandrine-bailleux-arm/sb/checkpatch-signoff

Mandate 'Signed-off-by' line in commit messages
diff --git a/.checkpatch.conf b/.checkpatch.conf
index c8a6084..0c84fcd 100644
--- a/.checkpatch.conf
+++ b/.checkpatch.conf
@@ -36,9 +36,6 @@
 # This is not Linux so don't expect a Linux tree!
 --no-tree
 
-# 'Signed-off-by' lines in commit messages are not mandated for TF.
---no-signoff
-
 # This clarifes the lines indications in the report.
 #
 # E.g.: