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

In the Linux kernel, the following vulnerability has been resolved:

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

If queue entry or DMA descriptor list allocation fails in

airoha_qdma_init_rx_queue routine, airoha_qdma_cleanup() will trigger a

NULL pointer dereference running netif_napi_del() for RX queue NAPIs

since netif_napi_add() has never been executed to this particular RX NAPI.

The issue is due to the early ndesc initialization in

airoha_qdma_init_rx_queue() since airoha_qdma_cleanup() relies on ndesc

value to check if the queue is properly initialized. Fix the issue moving

ndesc initialization at end of airoha_qdma_init_tx routine.

Move page_pool allocation after descriptor list allocation in order to

avoid memory leaks if desc allocation fails.