prima: Fix on suspecious defreferencing on Static code analysis

Added necessary NULL check to avoid dereferencing of a variable
that had NULL.

CRs-Fixed: 893694
Change-Id: Id45285dd8f6f674c6144be59b9706732c85d7018
diff --git a/CORE/HDD/src/wlan_hdd_softap_tx_rx.c b/CORE/HDD/src/wlan_hdd_softap_tx_rx.c
index 87f6bcf..7d5c1f0 100644
--- a/CORE/HDD/src/wlan_hdd_softap_tx_rx.c
+++ b/CORE/HDD/src/wlan_hdd_softap_tx_rx.c
@@ -318,6 +318,13 @@
        return os_status;
    }
 
+   if (pHddCtx == NULL)
+   {
+      VOS_TRACE(VOS_MODULE_ID_HDD_SAP_DATA, VOS_TRACE_LEVEL_ERROR,
+            FL("pHddCtx is NULL"));
+      goto xmit_done;
+   }
+
    pDestMacAddress = (v_MACADDR_t*)skb->data;
    
    ++pAdapter->hdd_stats.hddTxRxStats.txXmitCalled;