UPSTREAM: arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread()

[ Upstream commit 0100e6bb ]

In the arch addition of PF_IO_WORKER, I missed parisc and powerpc for
some reason. Fix that up, ensuring they handle PF_IO_WORKER like they do
PF_KTHREAD in copy_thread().

Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Fixes: 4727dc20 ("arch: setup PF_IO_WORKER threads like PF_KTHREAD")
Change-Id: I3d0289912eb9e4545fc0b680df6890b6b837ebdd
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit dd26e2ce)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>