Marvell/Drivers: Pp2Dxe: Switch to use MARVELL_BOARD_DESC protocol

Pp2Dxe driver used to get Armada7k8k PP2 controller description from
hardcoded values stored in the header file MvHwDescLib.h.
As a result it is very hard to support other Armada SoC families
with this driver.

This patch updates the driver to get PP2 controller description from
newly introduced MARVELL_BOARD_DESC protocol, and removes the dependency
on the hardcoded structures.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>