OvmfPkg: QemuVideoDxe: add virtio-vga support

OvmfPkg: QemuVideoDxe: add virtio-vga support

Qemu commit c5d4dac ("virtio-vga: add virtio gpu device with vga
compatibility") enables OVMF to drive the virtio-vga device:

The vga compatibility part of virtio-vga is identical to the qemu
standard vga, so supporting that is as easy as adding the PCI ID
to the list.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
[lersek@redhat.com: subject fixup and QEMU commit reference in commit msg]
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17690 6f19259b-4bc3-4df7-8a09-765794883524