qcacld-3.0: modify the assignment method of tstamp

Based on the current, Host driver assign a int value to tstamp directly.
But it is not compatible with previous kernel version.
Use function "ktime_set" to assign the value.

Change-Id: Id5fb5001e22aea8503c2dafbfef3fc8d27de1166
CRs-Fixed: 2549495

core/hdd/src/wlan_hdd_tsf.c

@@ -1454,7 +1454,7 @@ enum hdd_tsf_op_result hdd_netbuf_timestamp(qdf_nbuf_t netbuf,
 		if (!ret) {
 			hwtstamps.hwtstamp = soc_time;
 			*skb_hwtstamps(netbuf) = hwtstamps;
-			netbuf->tstamp = 0;
+			netbuf->tstamp = ktime_set(0, 0);
 			return HDD_TSF_OP_SUCC;
 		}
 	}
@@ -1543,7 +1543,7 @@ int hdd_rx_timestamp(qdf_nbuf_t netbuf, uint64_t target_time)
 		return 0;
 
 	/* reset tstamp when failed */
-	netbuf->tstamp = 0;
+	netbuf->tstamp = ktime_set(0, 0);
 	return -EINVAL;
 }