scftorture: Remove extraneous "scf" from per_version_boot_params

There is an extraneous "scf" in the per_version_boot_params shell function
used by scftorture.  No harm done in that it is just passed as an argument
to the /init program in initrd, but this commit nevertheless removes it.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>