docs: add guidelines for abandoning patches

The code review guidelines have been updated to explain when
patches that do not receive a response to the review comments
will be abandoned.

Change-Id: I60539e16ca41245cf1b352f24557be1b3c67c367
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
1 file changed