[MIPS] Make I8259A_IRQ_BASE customizable

Move I8259A_IRQ_BASE from asm/i8259.h to asm/mach-generic/irq.h and
make it really customizable.  And remove I8259_IRQ_BASE declared on
some platforms.  Currently only NEC_CMBVR4133 is using custom
I8259A_IRQ_BASE value.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/irq.h b/include/asm-mips/irq.h
index 386da82..91803ba 100644
--- a/include/asm-mips/irq.h
+++ b/include/asm-mips/irq.h
@@ -18,7 +18,7 @@
 #ifdef CONFIG_I8259
 static inline int irq_canonicalize(int irq)
 {
-	return ((irq == 2) ? 9 : irq);
+	return ((irq == I8259A_IRQ_BASE + 2) ? I8259A_IRQ_BASE + 9 : irq);
 }
 #else
 #define irq_canonicalize(irq) (irq)	/* Sane hardware, sane code ... */