ArmPkg: delete unused ArmTrustZoneSmc.h

ArmPkg: delete unused ArmTrustZoneSmc.h

ArmPkg/Include/IndustryStandard/ArmTrustZoneSmc.h contains definitions
contradicting the SMC Calling Convention (ARM DEN0028B).

It also has no users in public trees. So delete before it can cause
damage.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>