torture: Add "-enable-kvm -soundhw pcspk" to qemu command line

More recent qemu implementations really want "-enable-kvm", and the
"-soundhw pcspk" makes the script a bit less dependent on odd audio
libraries being installed.  This commit therefore adds both to the
default qemu command line.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>