wlan: Fix kernel panic calling ioctl setTrafficMon.

In this issue ,user data was acessed through wrqu->data.pointer.
But data is only passed by pointer if data size is more than
IFNAMSIZ (16 bytes) for fixed size private ioctl .If data size
is less than IFNAMSIZ then data can be acessed from extra_size.

As a part of fix, made sure that data is acessed through extra_size
parameter.

Change-Id: If4b544d95473e0a877c387e8252bce84ef02feb7
CRs-Fixed: 704425
diff --git a/CORE/HDD/src/wlan_hdd_hostapd.c b/CORE/HDD/src/wlan_hdd_hostapd.c
index 3d5a2ca..9a5bd30 100644
--- a/CORE/HDD/src/wlan_hdd_hostapd.c
+++ b/CORE/HDD/src/wlan_hdd_hostapd.c
@@ -1838,7 +1838,7 @@
         union iwreq_data *wrqu, char *extra)
 {
     hdd_adapter_t *pAdapter = WLAN_HDD_GET_PRIV_PTR(dev);
-    int *isSetTrafficMon = (int *)wrqu->data.pointer;
+    int *isSetTrafficMon = (int *)extra;
     hdd_context_t *pHddCtx;
     int status;