This patch adds support for the Undefined Behaviour sanitizer. There are
two types of support offered - minimalistic trapping support which
essentially immediately crashes on undefined behaviour and full support
with full debug messages.

The full support relies on ubsan.c which has been adapted from code used
by OPTEE.

Change-Id: I417c810f4fc43dcb56db6a6a555bfd0b38440727
Signed-off-by: Justin Chadwell <justin.chadwell@arm.com>