irqchip / GIC: Convert the GIC driver to ACPI probing

Now that we have a basic infrastructure to register irqchips and
call them on discovery of a matching entry in MADT, convert the
GIC driver to this new probing method.

It ends up being a code deletion party, which is a rather good thing.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/arm64/kernel/acpi.c

@@ -205,28 +205,3 @@ void __init acpi_boot_table_init(void)
 			disable_acpi();
 	}
 }
-
-void __init acpi_gic_init(void)
-{
-	struct acpi_table_header *table;
-	acpi_status status;
-	acpi_size tbl_size;
-	int err;
-
-	if (acpi_disabled)
-		return;
-
-	status = acpi_get_table_with_size(ACPI_SIG_MADT, 0, &table, &tbl_size);
-	if (ACPI_FAILURE(status)) {
-		const char *msg = acpi_format_exception(status);
-
-		pr_err("Failed to get MADT table, %s\n", msg);
-		return;
-	}
-
-	err = gic_v2_acpi_init(table);
-	if (err)
-		pr_err("Failed to initialize GIC IRQ controller");
-
-	early_acpi_os_unmap_memory((char *)table, tbl_size);
-}