MdeModulePkg: Add definitions for ATA AHCI host controller PPI

MdeModulePkg: Add definitions for ATA AHCI host controller PPI

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1409

This commit will add the definitions for ATA AHCI host controller PPI. The
purpose of the PPI in to provide:

* MMIO base address
* Controller identification information (DevicePath)

for ATA host controllers working under AHCI mode.

Cc: Jian J Wang <jian.j.wang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>