net: airoha: Move ndesc initialization at end of airoha_qdma_init_tx()

In the Linux kernel, the following vulnerability has been resolved: net: airoha: Move ndesc initialization at end of airoha_qdma_init_tx() If queue entry list allocation fails in airoha_qdma_init_tx_queue routine, airoha_qdma_cleanup_tx_queue() will trigger a NULL pointer dereference accessing the queue entry array. The issue is due to the early ndesc initialization in airoha_qdma_init_tx_queue(). Fix the issue moving ndesc initialization at end of airoha_qdma_init_tx routine.