ArmVirtPkg/PlatformBootManagerLib: remove empty PlatformBdsLib hooks

ArmVirtPkg/PlatformBootManagerLib: remove empty PlatformBdsLib hooks

Namely,
- PlatformBdsBootSuccess,
- PlatformBdsBootFail,
- PlatformBdsLockNonUpdatableFlash.

This patch parallels OvmfPkg commit 7f89929f7fb2.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ruiyu Ni <ruiyu.ni@Intel.com>