irqchip/mips-gic: Make local symbols static

The sparse tool complains as follows:

drivers/irqchip/irq-mips-gic.c:49:1: warning:
 symbol '__pcpu_scope_pcpu_masks' was not declared. Should it be static?
drivers/irqchip/irq-mips-gic.c:620:6: warning:
 symbol 'gic_ipi_domain_free' was not declared. Should it be static?
drivers/irqchip/irq-mips-gic.c:634:5: warning:
 symbol 'gic_ipi_domain_match' was not declared. Should it be static?

Those symbols are not used outside of irq-mips-gic.c, so marks
them static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200714142245.16124-1-weiyongjun1@huawei.com

drivers/irqchip/irq-mips-gic.c

@@ -46,7 +46,7 @@
 
 void __iomem *mips_gic_base;
 
-DEFINE_PER_CPU_READ_MOSTLY(unsigned long[GIC_MAX_LONGS], pcpu_masks);
+static DEFINE_PER_CPU_READ_MOSTLY(unsigned long[GIC_MAX_LONGS], pcpu_masks);
 
 static DEFINE_SPINLOCK(gic_lock);
 static struct irq_domain *gic_irq_domain;
@@ -617,7 +617,7 @@ static int gic_ipi_domain_alloc(struct irq_domain *d, unsigned int virq,
 	return ret;
 }
 
-void gic_ipi_domain_free(struct irq_domain *d, unsigned int virq,
+static void gic_ipi_domain_free(struct irq_domain *d, unsigned int virq,
 				unsigned int nr_irqs)
 {
 	irq_hw_number_t base_hwirq;
@@ -631,7 +631,7 @@ void gic_ipi_domain_free(struct irq_domain *d, unsigned int virq,
 	bitmap_set(ipi_available, base_hwirq, nr_irqs);
 }
 
-int gic_ipi_domain_match(struct irq_domain *d, struct device_node *node,
+static int gic_ipi_domain_match(struct irq_domain *d, struct device_node *node,
 				enum irq_domain_bus_token bus_token)
 {
 	bool is_ipi;