MdePkg: Add PI 1.4 Graphics HOB and PPI header files

MdePkg: Add PI 1.4 Graphics HOB and PPI header files

The PeiGraphicsPpi is the main interface exposed by the Graphics PEIM to
be used by the other firmware modules.

When graphics capability is included in PEI, it produces a
EFI_PEI_GRAPHICS_INFO_HOB which provides information about the graphics
mode and the framebuffer.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17233 6f19259b-4bc3-4df7-8a09-765794883524