Marvell/Armada7k8k: Extend ArmadaSoCDescLib with AHCI/SDMMC/XHCI

This patch introduces new library callbacks for NonDiscoverable devices
i.e. AHCI/XHCI/SDMMC. They dynamically allocate and fill according
structures with the SoC description of the devices.

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