x86/irq: Remove unused pre_init_apic_IRQ0()

Now there's no user of pre_init_apic_IRQ0(), so remove it.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Grant Likely <grant.likely@linaro.org>
Link: http://lkml.kernel.org/r/1428905519-23704-32-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/io_apic.h

@@ -204,7 +204,6 @@ extern int mp_irqdomain_map(struct irq_domain *domain, unsigned int virq,
 			    irq_hw_number_t hwirq);
 extern void mp_irqdomain_unmap(struct irq_domain *domain, unsigned int virq);
 extern int mp_set_gsi_attr(u32 gsi, int trigger, int polarity, int node);
-extern void __init pre_init_apic_IRQ0(void);
 
 extern void mp_save_irq(struct mpc_intsrc *m);
 

arch/x86/kernel/apic/io_apic.c

@@ -3091,20 +3091,3 @@ int mp_set_gsi_attr(u32 gsi, int trigger, int polarity, int node)
 
 	return ret;
 }
-
-/* Enable IOAPIC early just for system timer */
-void __init pre_init_apic_IRQ0(void)
-{
-	struct io_apic_irq_attr attr = { 0, 0, 0, 0 };
-
-	printk(KERN_INFO "Early APIC setup for system timer0\n");
-#ifndef CONFIG_SMP
-	physid_set_mask_of_physid(boot_cpu_physical_apicid,
-					 &phys_cpu_present_map);
-#endif
-	setup_local_APIC();
-
-	io_apic_setup_irq_pin(0, 0, &attr);
-	irq_set_chip_and_handler_name(0, &ioapic_chip, handle_edge_irq,
-				      "edge");
-}