This function scans a string backwards from the end for the first
instance of a character.

Change-Id: I46b21573ed25a0ff222eac340e1e1fb93b040763
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>

Ambroise Vincent authored on 19 Jun 2019 Olivier Deprez committed on 11 Dec 2019