Reset client pointer to NULL after returning from vos_mem_free()

In the PE Module resetting the pointer to NULL is done by this
commit.

Change-Id: I19699556a798c353bcecde33021d8832cc10f8cb
CRs-fixed: 586361
diff --git a/CORE/MAC/src/pe/lim/limSession.c b/CORE/MAC/src/pe/lim/limSession.c
index 97ecaab..caf444a 100644
--- a/CORE/MAC/src/pe/lim/limSession.c
+++ b/CORE/MAC/src/pe/lim/limSession.c
@@ -140,6 +140,7 @@
             {
                 limLog(pMac, LOGE, FL("memory allocate failed!"));
                 vos_mem_free(pMac->lim.gpSession[i].dph.dphHashTable.pHashTable);
+                pMac->lim.gpSession[i].dph.dphHashTable.pHashTable = NULL;
                 return NULL;
             }
             pMac->lim.gpSession[i].dph.dphHashTable.size = numSta;
@@ -154,6 +155,8 @@
                 PELOGE(limLog(pMac, LOGE, FL("memory allocate failed!"));)
                 vos_mem_free(pMac->lim.gpSession[i].dph.dphHashTable.pHashTable);
                 vos_mem_free(pMac->lim.gpSession[i].dph.dphHashTable.pDphNodeArray);
+                pMac->lim.gpSession[i].dph.dphHashTable.pHashTable = NULL;
+                pMac->lim.gpSession[i].dph.dphHashTable.pDphNodeArray = NULL;
                 return NULL;
             }
             vos_mem_set(pMac->lim.gpSession[i].gpLimPeerIdxpool,