ArmVirtualizationPkg/ArmVirtualizationQemu: add VGA console output

ArmVirtualizationPkg/ArmVirtualizationQemu: add VGA console output

Alex Graf's QEMU patchset enables "-device VGA" for the virt machtype as
well. We can now include OvmfPkg/QemuVideoDxe in the firmware, and set
PcdDefaultConOutPaths such that the console output is multiplexed to the
video window as well. (Our platform BDS lib doesn't (yet) locate the VGA
device automatically.)

OvmfPkg/PlatformDxe is included too; it allows users to select a video
resolution. (Note that PcdSetupVideoHorizontalResolution and
PcdSetupVideoVerticalResolution are independent; see git commit 848834cb
(SVN r16311) for explanation.)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Olivier Martin <Olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16913 6f19259b-4bc3-4df7-8a09-765794883524