ionic: minimal work with 0 budget

We should be doing as little as possible besides freeing Tx
space when our napi routines are called with budget of 0, so
jump out before doing anything besides Tx cleaning.

See commit afbed3f7 ("net/mlx5e: do as little as possible in napi poll when budget is 0")
for more info.

Fixes: fe8c30b5 ("ionic: separate interrupt for Tx and Rx")
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20240210001307.48450-1-shannon.nelson@amd.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/pensando/ionic/ionic_txrx.c

@@ -579,6 +579,9 @@ int ionic_tx_napi(struct napi_struct *napi, int budget)
 	work_done = ionic_cq_service(cq, budget,
 				     ionic_tx_service, NULL, NULL);
 
+	if (unlikely(!budget))
+		return budget;
+
 	if (work_done < budget && napi_complete_done(napi, work_done)) {
 		ionic_dim_update(qcq, IONIC_LIF_F_TX_DIM_INTR);
 		flags |= IONIC_INTR_CRED_UNMASK;
@@ -607,6 +610,9 @@ int ionic_rx_napi(struct napi_struct *napi, int budget)
 	u32 work_done = 0;
 	u32 flags = 0;
 
+	if (unlikely(!budget))
+		return budget;
+
 	lif = cq->bound_q->lif;
 	idev = &lif->ionic->idev;
 
@@ -656,6 +662,9 @@ int ionic_txrx_napi(struct napi_struct *napi, int budget)
 	tx_work_done = ionic_cq_service(txcq, IONIC_TX_BUDGET_DEFAULT,
 					ionic_tx_service, NULL, NULL);
 
+	if (unlikely(!budget))
+		return budget;
+
 	rx_work_done = ionic_cq_service(rxcq, budget,
 					ionic_rx_service, NULL, NULL);