qcacmn: Check NULL before derefencing pPacket from htc_packet_dequeue

Add NULL check for pPacket returned from htc_packet_dequeue before
dereferencing it.

Change-Id: I30c4fb3a4bc6652396795305c3b8a23bba88922a
CRs-fixed: 2009829

htc/htc_recv.c

@@ -114,6 +114,9 @@ static void do_recv_completion(HTC_ENDPOINT *pEndpoint,
 							("HTC ep %d has NULL recv callback on packet %p\n",
 							 pEndpoint->Id,
 							 pPacket));
+					if (pPacket)
+						qdf_nbuf_free(
+							pPacket->pPktContext);
 					continue;
 				}
 				AR_DEBUG_PRINTF(ATH_DEBUG_RECV,