net: airoha: Fix NULL pointer dereference in airoha_qdma_cleanup_rx_queue()

Move page_pool_get_dma_dir() inside the while loop of
airoha_qdma_cleanup_rx_queue routine in order to avoid possible NULL
pointer dereference if airoha_qdma_init_rx_queue() fails before
properly allocating the page_pool pointer.

Fixes: 23020f04 ("net: airoha: Introduce ethernet support for EN7581 SoC")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/7330a41bba720c33abc039955f6172457a3a34f0.1721205981.git.lorenzo@kernel.orgSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/mediatek/airoha_eth.c

@@ -1585,7 +1585,6 @@ static int airoha_qdma_init_rx_queue(struct airoha_eth *eth,
 
 static void airoha_qdma_cleanup_rx_queue(struct airoha_queue *q)
 {
-	enum dma_data_direction dir = page_pool_get_dma_dir(q->page_pool);
 	struct airoha_eth *eth = q->eth;
 
 	while (q->queued) {
@@ -1593,7 +1592,7 @@ static void airoha_qdma_cleanup_rx_queue(struct airoha_queue *q)
 		struct page *page = virt_to_head_page(e->buf);
 
 		dma_sync_single_for_cpu(eth->dev, e->dma_addr, e->dma_len,
-					dir);
+					page_pool_get_dma_dir(q->page_pool));
 		page_pool_put_full_page(q->page_pool, page, false);
 		q->tail = (q->tail + 1) % q->ndesc;
 		q->queued--;