rcutorture: Add --qemu-args argument to kvm.sh

This commits adds the --qemu-args argument to kvm.sh that is required
to pass boot devices down through to qemu.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Greg KH <gregkh@linuxfoundation.org>

diff --cc tools/testing/selftests/rcutorture/bin/kvm.sh
Simple merge