ANDROID: Move SCX_OPS_DISABLING VH inside the scx_fork_rwsem section

[Replacement commit for the original that somehow ended up empty.]

We found a stability issue in current code of scx_ops_disable_workfn
founction. When SCX_OPS_DISABLING VH is invoked, system may keeps
forking fair tasks. In this circumstances, if scx_ops_disable_workfn
is blocked by scx_fork_rwsem, it may never running again because the
task who invoking scx_ops_disable_workfn is scx task.

So we move the SCX_OPS_DISABLING VH inside scx_fork_rwsem section.

This patchset ensures that if the scx task who invoking
scx_ops_disable_workfn is blocked by scx_fork_rwsem, the system will
not produce fair task. This can avoid the stability issue caused in
scx disabling process.

Bug: 439095466

Change-Id: I6a3610e34ee9722c3e685c6843853fff1347c757
Signed-off-by: ZhiFeng Gao <gaozhifeng@oppo.com>
Bug: 448317641
Fixes: c9584d7f ("ANDROID: Move SCX_OPS_DISABLING VH inside the scx_fork_rwsem section")
Signed-off-by: Giuliano Procida <gprocida@google.com>