rcutorture: Drop "-soundhw pcspkr" from x86 boot arguments

Because recent testing shows that "-soundhw pcspkr" is no longer required
in the kernel boot arguments, this commit drops this qemu argument.
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

tools/testing/selftests/rcutorture/bin/functions.sh

@@ -171,7 +171,6 @@ identify_qemu_append () {
 identify_qemu_args () {
 	case "$1" in
 	qemu-system-x86_64|qemu-system-i386)
-		echo -soundhw pcspk
 		;;
 	qemu-system-ppc64)
 		echo -enable-kvm -M pseries -nodefaults