Sync patches r14657 and r14659 from main trunk.
1. MdeModulePkg/NvmExpressDxe: Fix some bugs
   1) The Queue size field in create I/O submission/completion queue cmds is 0-based. the current code is 1-based.
   2) A typo on allocated memory page size. it's inconsistent that some places is using 4 pages, but a place is using 6 pages.
   3) A typo on PRP/SGL mechanism judgment. should directly use Psdt field rather than Opc field.
   4) Some platforms may not support UINT64 width access on MMIO register. Fix it to use two 32-bit width access.
2. Update BGRT image buffer to be stored in EfiBootSerivesData according to ACPI5.0 spec.


git-svn-id: https://svn.code.sf.net/p/edk2/code/branches/UDK2010.SR1@14670 6f19259b-4bc3-4df7-8a09-765794883524