ArmVirtPkg: signal EndOxDxe event in PlatformBsdInit

ArmVirtPkg: signal EndOxDxe event in PlatformBsdInit

Currently, the ArmVirtPkg platforms built with the Intel BDS fail
to signal the end-of-DXE event 'gEfiEndOfDxeEventGroupGuid' when
entering the BDS phase, which results in some loss of functionality,
i.e., variable reclaim in the VariableDxe drivers, and the splitting
of the memory regions that is part of the recently added UEFI 2.5
properties table feature.

As discussed on the edk2-devel mailing list here:

http://thread.gmane.org/gmane.comp.bios.tianocore.devel/16088/focus=16109

it is up to the platform BDS to signal that event, since there may be
platform specific ordering constraints with respect to the signalling
of the event that are difficult to honor at the generic level.

So add the SignalEvent () call to PlatformBdsInit () of ArmVirtPkg's
PlatformBdsLib implementation for the Intel BDS.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17713 6f19259b-4bc3-4df7-8a09-765794883524