Revert "ppc64: tackle SRCU hang issue"
    
    Resolves: bz2177574
    Upstream: RHEL-only
    
    This reverts commit 870ec2ec936f23076ab9f35ae9dcdf44fe26b703.
    
    Now the real fix has gone into the RHEL-9 kernel [1], the temporary
    workaround can be removed.
    
    [1]: https://bugzilla.redhat.com/show_bug.cgi?id=2129726
    
    Signed-off-by: Pingfan Liu <piliu@redhat.com>