x86: automatical unification of i8259.c

Make conversion of i8259 very mechanical -- i8259 was generated by
diff --git a/include/asm-x86/i8259.h b/include/asm-x86/i8259.h
index 45d4df3..2f98df9 100644
--- a/include/asm-x86/i8259.h
+++ b/include/asm-x86/i8259.h
@@ -55,4 +55,6 @@
 	udelay(2);
 }
 
+extern struct irq_chip i8259A_chip;
+
 #endif	/* __ASM_I8259_H__ */