irqchip/mips-gic: Check the return value of ioremap() in gic_of_init()

The function ioremap() in gic_of_init() can fail, so
its return value should be checked.
Reported-by: NHacash Robot <hacashRobot@santino.com>
Signed-off-by: NWilliam Dean <williamsukatube@163.com>
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220723100128.2964304-1-williamsukatube@163.com

drivers/irqchip/irq-mips-gic.c

@@ -734,6 +734,10 @@ static int __init gic_of_init(struct device_node *node,
 	}
 
 	mips_gic_base = ioremap(gic_base, gic_len);
+	if (!mips_gic_base) {
+		pr_err("Failed to ioremap gic_base\n");
+		return -ENOMEM;
+	}
 
 	gicconfig = read_gic_config();
 	gic_shared_intrs = FIELD_GET(GIC_CONFIG_NUMINTERRUPTS, gicconfig);