Update meson platform to not rely on undefined overflow behaviour
Update meson platform to not rely on undefined overflow behaviour

This consists of ensuring that the left operand of each shift is
unsigned when the operation might overflow into the sign bit.

Change-Id: Ib7ec8ed3423e9b9b32be2388520bc27ee28f6370
Signed-off-by: Justin Chadwell <23868ac6bb803cbca62577fbb15c1a832c6e5215@arm.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware