Marvell/Armada7k8k: Fix 32-bit compilation

It turned out, that the recently added features broke
ARM compilation. Fix all issues:
* Update signatures types in structures (UINTN -> UINT64)
* Use fixed type for address in ICU
* Limit memory for ARM build to 1GB and stop using non-existent PCD

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>