clocksource/drivers/ralink: Fix resource leaks in init error path

The ralink_systick_init() function does not release all acquired resources
on its error paths. If irq_of_parse_and_map() or a subsequent call fails,
the previously created I/O memory mapping and IRQ mapping are leaked.

Add goto-based error handling labels to ensure that all allocated
resources are correctly freed.

Fixes: 1f2acc5 ("MIPS: ralink: Add support for systick timer found on newer ralink SoC")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20251030090710.1603-1-vulab@iscas.ac.cn

Author: ISCAS-Vulab

drivers/clocksource/timer-ralink.c

@@ -130,21 +130,28 @@ static int __init ralink_systick_init(struct device_node *np)
 	systick.dev.irq = irq_of_parse_and_map(np, 0);
 	if (!systick.dev.irq) {
 		pr_err("%pOFn: request_irq failed", np);
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_iounmap;
 	}
 
 	ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
 				    SYSTICK_FREQ, 301, 16,
 				    clocksource_mmio_readl_up);
 	if (ret)
-		return ret;
+		goto err_free_irq;
 
 	clockevents_register_device(&systick.dev);
 
 	pr_info("%pOFn: running - mult: %d, shift: %d\n",
 			np, systick.dev.mult, systick.dev.shift);
 
 	return 0;
+
+err_free_irq:
+	irq_dispose_mapping(systick.dev.irq);
+err_iounmap:
+	iounmap(systick.membase);
+	return ret;
 }
 
 TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);