ArmVirtPkg: resolve PciCapLib, PciCapPciSegmentLib, PciCapPciIoLib

ArmVirtPkg: resolve PciCapLib, PciCapPciSegmentLib, PciCapPciIoLib

Resolve the PciCapLib, PciCapPciSegmentLib, and PciCapPciIoLib classes to
their single respective instances under OvmfPkg. Later patches will use
those lib classes in OvmfPkg drivers, some of which are included in
ArmVirt platforms.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>