checkpatch: add Suggested-by as a standard signature

As people started using Suggested-by as standard signature, adding
"Suggested-by" to the standard signature so that checkpatch won't
generate warning when Suggested-by is used in patch signature

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
index aa0c1e6..6e97e73 100644
--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -420,7 +420,7 @@
 have been included in the discussion
 
 
-14) Using Reported-by:, Tested-by: and Reviewed-by:
+14) Using Reported-by:, Tested-by:, Reviewed-by: and Suggested-by:
 
 If this patch fixes a problem reported by somebody else, consider adding a
 Reported-by: tag to credit the reporter for their contribution.  Please
@@ -468,6 +468,13 @@
 understand the subject area and to perform thorough reviews, will normally
 increase the likelihood of your patch getting into the kernel.
 
+A Suggested-by: tag indicates that the patch idea is suggested by the person
+named and ensures credit to the person for the idea. Please note that this
+tag should not be added without the reporter's permission, especially if the
+idea was not posted in a public forum. That said, if we diligently credit our
+idea reporters, they will, hopefully, be inspired to help us again in the
+future.
+
 
 15) The canonical patch format