Update resource degrade algorithm in PCI bus driver. (1)If any child device has both...

Update resource degrade algorithm in PCI bus driver. (1)If any child device has both option ROM and 64-bit BAR, degrade its PMEM64/MEM64 requests in case that if a legacy option ROM image can not access 64-bit resources. (2)      If there are both PMEM64 and PMEM32 requests from child devices, which can not be satisfied by a P2P bridge simultaneously, keep PMEM64 and degrade PMEM32 to MEM32. (3) PMEM64/MEM64 are not supported when firmware is in 32-bit mode.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9599 6f19259b-4bc3-4df7-8a09-765794883524