x86: move eisa_set_level_irq declaration to header

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/acpi/boot.c

@@ -507,8 +507,6 @@ int acpi_register_gsi(u32 gsi, int triggering, int polarity)
 	 * Make sure all (legacy) PCI IRQs are set as level-triggered.
 	 */
 	if (acpi_irq_model == ACPI_IRQ_MODEL_PIC) {
-		extern void eisa_set_level_irq(unsigned int irq);
-
 		if (triggering == ACPI_LEVEL_SENSITIVE)
 			eisa_set_level_irq(gsi);
 	}

include/asm-x86/hw_irq.h

@@ -79,6 +79,9 @@ extern void send_IPI(int dest, int vector);
 extern atomic_t irq_err_count;
 extern atomic_t irq_mis_count;
 
+/* EISA */
+extern void eisa_set_level_irq(unsigned int irq);
+
 /* Voyager functions */
 extern asmlinkage void vic_cpi_interrupt(void);
 extern asmlinkage void vic_sys_interrupt(void);