Pal: revert changes to avoid potential priority inversion issue

Revert "PAL: Adding a new mutex for checking if stream is valid"
This reverts commit 9e641e481e1bb0b9afc57de2724df51616b5b5e8.

Revert "pal: Use increase/decrease StreamUserCounter to protect getTimestamp"
This reverts commit 9354795c76307ace083ddcc423e7f3221caedb22.

Revert "PAL: Check if stream_handle is valid before accessing"
This reverts commit a0ca34887193624afc0f339ca3f9a4fd47eabb5d.

Reason for reverting: There is a potential priority inversion issue
in pal_stream_write with those changes.

Change-Id: Icb13dcabacc71d8444a8c173249316407d72662e
(cherry picked from commit 90c7c0906768ac30f8911acb33aa629209dda2e6)
3 files changed