OvmfPkg/PlatformPei: Initialise RCBA (B0:D31:F0 0xf0) register

OvmfPkg/PlatformPei: Initialise RCBA (B0:D31:F0 0xf0) register

This patch initialises root complex register block BAR in order to
support TCO watchdog emulation features (e.g. reboot upon NO_REBOOT bit
not set) on QEMU.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
Reviewed-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@17601 6f19259b-4bc3-4df7-8a09-765794883524