x86: Add a function to set the IOAPIC ID

Add a function to set the ID in the IOAPIC.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/include/asm/ioapic.h b/arch/x86/include/asm/ioapic.h
index 77c443e..2feed86 100644
--- a/arch/x86/include/asm/ioapic.h
+++ b/arch/x86/include/asm/ioapic.h
@@ -39,4 +39,6 @@
  */
 void io_apic_write(u32 reg, u32 val);
 
+void io_apic_set_id(int ioapic_id);
+
 #endif