ArmVirtPkg: introduce ArmVirtMemInfoLib library class

As part of the effort to get rid of ArmPlatformLib (which incorporates
far too many duties in a single library), introduce ArmVirtMemInfoLib
which will be invoked by our ArmVirtMemoryInitPeiLib implementation to
get a description of the virtual address space. This will allow us to
remove this functionality from ArmPlatformLib later, or, in the case of
ArmVirtXen and ArmVirtQemuKernel, drop ArmPlatformLib altogether.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

ArmVirtPkg/ArmVirtPkg.dec

@@ -30,6 +30,9 @@
 [Includes.common]
   Include                        # Root include for the package
 
+[LibraryClasses]
+  ArmVirtMemInfoLib|Include/Library/ArmVirtMemInfoLib.h
+
 [Guids.common]
   gArmVirtTokenSpaceGuid = { 0x0B6F5CA7, 0x4F53, 0x445A, { 0xB7, 0x6E, 0x2E, 0x36, 0x5B, 0x80, 0x63, 0x66 } }
   gEarlyPL011BaseAddressGuid       = { 0xB199DEA9, 0xFD5C, 0x4A84, { 0x80, 0x82, 0x2F, 0x41, 0x70, 0x78, 0x03, 0x05 } }