OvmfPkg/PlatformPei: emulated NV storage must be EfiRuntimeServicesData

OvmfPkg/PlatformPei: emulated NV storage must be EfiRuntimeServicesData

SVN r14770 ("OvmfPkg/PlatformPei: correctly align emulated NV storage")
made sure the emulated NV storage was allocated with correct alignment.

However, the AllocateRuntimePool() -> AllocateAlignedPages() change
flipped the memory type from EfiRuntimeServicesData to
EfiBootServicesData. This causes variable services to access freed storage
at runtime. It crashes Windows 2008 R2 early at boot, for example.

Keep the alignment, but restore the memory type to EfiRuntimeServicesData,
by calling AllocateAlignedRuntimePages().

These helper functions are implemeted and documented in
"MdePkg/Library/PeiMemoryAllocationLib/MemoryAllocationLib.c".

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14806 6f19259b-4bc3-4df7-8a09-765794883524