OvmfPkg/PlatformPei: Add Xen support

* Make PlatformPei aware of Xen
* Fix assigned PIO and MMIO ranges to be compatible with Xen
* Reserve Xen HVM address range
* Publish XenInfo HOB
* Don't program PIIX4 PMBA for Xen

Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Reviewed-by: gavinguan
Signed-off-by: jljusten

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12091 6f19259b-4bc3-4df7-8a09-765794883524
4 files changed