qemu: remove memset params array to zero in qemuDomainGetPercpuStats

the array params is allocated by VIR_ALLOC_N in
remoteDispatchDomainGetCPUStats. it had been set
to zero. No need to reset it to zero again, and
this reset here is incorrect too, nparams * ncpus
is the array length not the size of params array.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>

src/qemu/qemu_driver.c

@@ -15881,7 +15881,6 @@ qemuDomainGetPercpuStats(virDomainObjPtr vm,
     if (virCgroupGetCpuacctPercpuUsage(priv->cgroup, &buf))
         goto cleanup;
     pos = buf;
-    memset(params, 0, nparams * ncpus);
 
     /* return percpu cputime in index 0 */
     param_idx = 0;