qcacld-2.0: reduce htt descriptor memory foot print

When allocate HTT descriptor, instead of allocating
large single chunk of memory, allocate small sized multiple
chunk of memory. Then not need to allocate order 5 memory.
Will have less chance to have out of memory problem.

Change-Id: Ib9d4a3f10adbc0656e1418cf3a67429322bb7164
CRs-fixed: 845666
diff --git a/CORE/CLD_TXRX/TXRX/ol_tx_desc.h b/CORE/CLD_TXRX/TXRX/ol_tx_desc.h
index a310954..8e7ebb7 100644
--- a/CORE/CLD_TXRX/TXRX/ol_tx_desc.h
+++ b/CORE/CLD_TXRX/TXRX/ol_tx_desc.h
@@ -148,11 +148,8 @@
 static inline u_int16_t
 ol_tx_desc_id(struct ol_txrx_pdev_t *pdev, struct ol_tx_desc_t *tx_desc)
 {
-    TXRX_ASSERT2(
-        ((union ol_tx_desc_list_elem_t *) tx_desc - pdev->tx_desc.array) <
-        pdev->tx_desc.pool_size);
-    return (u_int16_t)
-        ((union ol_tx_desc_list_elem_t *)tx_desc - pdev->tx_desc.array);
+    TXRX_ASSERT2(tx_desc->id < pdev->tx_desc.pool_size);
+    return tx_desc->id;
 }
 /*
  * @brief Retrieves the beacon headr for the vdev