rpi3: Add support for the stack protector

It uses the hardware RNG in a similar way as Juno (it gets 128 bits of
entropy and does xor on them).

It is disabled by default.

Change-Id: I8b3adb61f5a5623716e0e8b6799404c68dd94c60
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
3 files changed