Some of the affected macros can only be used from C code. In general, we
use arch_helpers.h for any C helpers to access registers. For
consistency, the other macros have been moved as well.

Also, import some AArch32 helpers from TF-A-Tests.

Change-Id: Ie8fe1ddeadba5336c12971ddc39a7883121386b1
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>