Remove no longer needed ppc64 workaround
    
    The kernel bug causing failures on ppc64le is now fixed in recent/stable
    kernels [1], so we can remove the workaround.
    
    [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=dcf7b48212c0fab7df69e84fab22d6cb7c8c0fb9
    
    Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>