ArmPlatformPkg: move to ArmPkg version of PeiServicesTablePointerLib

ArmPlatformPkg: move to ArmPkg version of PeiServicesTablePointerLib

As pointed out by Eugene, the ArmPlatformPkg implementation of
PeiServicesTablePointerLib violates the PI sec, since it uses
ArmPlatformGlobalVariableLib to store the PEI services table pointer
rather than the thread ID cpu registers as the spec requires.

So instead, move to the ArmPkg version of this library, which does
adhere to the PI spec.

Reported-by: Eugene Cohen <eugene@hp.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18987 6f19259b-4bc3-4df7-8a09-765794883524