MdePkg/BaseSynchronizationLib: fix AArch64 return values

MdePkg/BaseSynchronizationLib: fix AArch64 return values

Fix the wrong return value of both InternalSyncIncrement()
and InternalSyncDecrement(). The return value shouldn't
be the address of input parameter. It should be the updated
value of input parameter instead.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Haojian Zhuang <haojian.zhuang@linaro.org>
Reviewed-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@18685 6f19259b-4bc3-4df7-8a09-765794883524