wlan: Use offset to get the ie length from bss descriptor

The length of bss descriptor is calculated using offset of IE
field but when lim tries to get the IE length it doesnt use the
offset which results in incorrect IE length.

To fix use offset to get the ie length from bss descriptor

Change-Id: I7abbde83aea1e0a1cfcd7bdb1a184158f75f2455
CRs-Fixed: 1082001
diff --git a/CORE/SME/src/csr/csrUtil.c b/CORE/SME/src/csr/csrUtil.c
index 3e2732f..52687fe 100644
--- a/CORE/SME/src/csr/csrUtil.c
+++ b/CORE/SME/src/csr/csrUtil.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011-2015 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2011-2016 The Linux Foundation. All rights reserved.
  *
  * Previously licensed under the ISC license by Qualcomm Atheros, Inc.
  *
@@ -2064,7 +2064,7 @@
 {
     eHalStatus status = eHAL_STATUS_FAILURE;
     tpAniSirGlobal pMac = PMAC_STRUCT( hHal );
-    int ieLen = (int)(pBssDesc->length + sizeof( pBssDesc->length ) - GET_FIELD_OFFSET( tSirBssDescription, ieFields ));
+    int ieLen = (int)GET_IE_LEN_IN_BSS(pBssDesc->length);
 
     if(ieLen > 0 && pIEStruct)
     {