Marvell/Cn9132Db: Introduce board support

This patch introduces all necessary components required
for building EDK2 firmware for CN9132-DB setup A. Note
the ACPI is not yet available for this variant, due to
the current ICU (CP1xx interrupt controller) support
implementation.

In order to build this variant, '-D CN9132' flag should be added.

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