Fix below warning by using proper ktime helper to calculate timeslice.
CHECK   drivers/gpu/drm/i915//gvt/sched_policy.c
drivers/gpu/drm/i915//gvt/sched_policy.c:108 gvt_balance_timeslice() debug: sval_binop_signed: invalid divide LLONG_MIN/-1
drivers/gpu/drm/i915//gvt/sched_policy.c:108 gvt_balance_timeslice() debug: sval_binop_signed: invalid divide LLONG_MIN/-1
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
 
                list_for_each(pos, &sched_data->lru_runq_head) {
                        vgpu_data = container_of(pos, struct vgpu_sched_data, lru_list);
-                       fair_timeslice = ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS) *
-                                               vgpu_data->sched_ctl.weight /
-                                               total_weight;
+                       fair_timeslice = ktime_divns(ms_to_ktime(GVT_TS_BALANCE_PERIOD_MS),
+                                                    total_weight) * vgpu_data->sched_ctl.weight;
 
                        vgpu_data->allocated_ts = fair_timeslice;
                        vgpu_data->left_ts = vgpu_data->allocated_ts;