net: stmmac: Simplify mtl IRQ status checking

Commit 8a7cb245 ("net: stmmac: Do not enable RX FIFO overflow
interrupts") disabled the RX FIFO overflow interrupts. However, it left the
status variable around, but never checks it.

As stmmac_host_mtl_irq_status() returns only 0 now, the code can be
simplified.
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Link: https://lore.kernel.org/r/20240208-stmmac_irq-v1-1-8bab236026d4@linutronix.deSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -6061,10 +6061,8 @@ static void stmmac_common_interrupt(struct stmmac_priv *priv)
 				priv->tx_path_in_lpi_mode = false;
 		}
 
-		for (queue = 0; queue < queues_count; queue++) {
-			status = stmmac_host_mtl_irq_status(priv, priv->hw,
-							    queue);
-		}
+		for (queue = 0; queue < queues_count; queue++)
+			stmmac_host_mtl_irq_status(priv, priv->hw, queue);
 
 		/* PCS link status */
 		if (priv->hw->pcs &&