Marvell/Drivers: MvBoardDesc: Extend protocol with PP2 support

Introduce new callback that can provide information
about PP2 NICs to the Pp2Dxe driver.

Extend ArmadaBoardDescLib with new structure MV_BOARD_PP2_DESC,
for holding board specific data. In further steps it should
be extended and replace PCD port's representation with the
appropriate structures.

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