irqchip/loongson-pch-pic: Fix pch_pic_acpi_init calling

For dual-bridges scenario, pch_pic_acpi_init() will be called
in following path:

cpuintc_acpi_init
  acpi_cascade_irqdomain_init(in cpuintc driver)
    acpi_table_parse_madt
      eiointc_parse_madt
        eiointc_acpi_init /* this will be called two times
                             correspondingto parsing two
                             eiointc entries in MADT under
                             dual-bridges scenario*/
          acpi_cascade_irqdomain_init(in eiointc driver)
            acpi_table_parse_madt
              pch_pic_parse_madt
                pch_pic_acpi_init /* this will be called depend
                                     on valid parent IRQ domain
                                     handle for one or two times
                                     corresponding to parsing
                                     two pchpic entries in MADT
                                     druring calling
                                     eiointc_acpi_init() under
                                     dual-bridges scenario*/

During the first eiointc_acpi_init() calling, the
pch_pic_acpi_init() will be called just one time since only
one valid parent IRQ domain handle will be found for current
eiointc IRQ domain.

During the second eiointc_acpi_init() calling, the
pch_pic_acpi_init() will be called two times since two valid
parent IRQ domain handles will be found. So in pch_pic_acpi_init(),
we must have a reasonable way to prevent from creating second same
pch_pic IRQ domain.

The patch matches gsi base information in created pch_pic IRQ
domains to check if the target domain has been created to avoid the
bug mentioned above.

Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>

Author: lvjianmin-loongson

drivers/irqchip/irq-loongson-pch-pic.c

@@ -404,6 +404,9 @@ int __init pch_pic_acpi_init(struct irq_domain *parent,
 	int ret, vec_base;
 	struct fwnode_handle *domain_handle;
 
+	if (find_pch_pic(acpi_pchpic->gsi_base) >= 0)
+		return 0;
+
 	vec_base = acpi_pchpic->gsi_base - GSI_MIN_PCH_IRQ;
 
 	domain_handle = irq_domain_alloc_fwnode(&acpi_pchpic->address);