host-validate: Fix suggestion for missing cpu cgroup

If the cpu cgroup is not found when validating an host for
LXC support, virt-host-validate will suggest to enable the
CONFIG_CGROUP_SCHED kconfig option.

The appropriate option is really CONFIG_CGROUP_CPU. The
QEMU checks already get that right, so no changes needed.

tools/virt-host-validate-lxc.c

@@ -70,7 +70,7 @@ int virHostValidateLXC(void)
 
     if (virHostValidateCGroupController("LXC", "cpu",
                                         VIR_HOST_VALIDATE_FAIL,
-                                        "CGROUP_SCHED") < 0)
+                                        "CGROUP_CPU") < 0)
         ret = -1;
 
     if (virHostValidateCGroupController("LXC", "cpuacct",