[2405] Revert "ArmPkg: ArmPsciMpServicesDxe: Fix CPU resource leakage" (#256)

# Preface

Please ensure you have read the [contribution
docs](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md) prior
to submitting the pull request. In particular,
[pull request
guidelines](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md#pull-request-best-practices).

## Description

This reverts commit 05caf20. As the
change was integrated into EDK2 in a different way which will cover the
expected CPU state to fix the state machine.

For each item, place an "x" in between `[` and `]` if true. Example:
`[x]`.
_(you can also check items in the GitHub UI)_

- [x] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

This change was tested on QEMU SBSA and verified MP test works as
expected.

## Integration Instructions

N/A

Author: kuqin12

ArmPkg/Drivers/ArmPsciMpServicesDxe/ArmPsciMpServicesDxe.c

@@ -754,13 +754,6 @@ StartupThisAP (
     return EFI_SUCCESS;
   }
 
-  // MU_CHANGE: Set the timer anyway, otherwise this AP is spent on this boot if the AP routine timeout.
-  gBS->SetTimer (
-         CpuData->CheckThisAPEvent,
-         TimerPeriodic,
-         POLL_INTERVAL_US
-         );
-
   // Blocking
   while (TRUE) {
     if (GetApState (CpuData) == CpuStateFinished) {