ArmPlatformPkg: signal EndOfDxe event in PlatformBsdInit

ArmPlatformPkg: signal EndOfDxe event in PlatformBsdInit

Like the ArmVirtPkg platforms up until SVN r17713, the ArmPlatformPkg
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 ArmPlatformPkg'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>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18394 6f19259b-4bc3-4df7-8a09-765794883524