[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/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c
index b59a676..91de422 100644
--- a/arch/mips/kernel/i8259.c
+++ b/arch/mips/kernel/i8259.c
@@ -54,9 +54,11 @@
 
 void disable_8259A_irq(unsigned int irq)
 {
-	unsigned int mask = 1 << irq;
+	unsigned int mask;
 	unsigned long flags;
 
+	irq -= I8259A_IRQ_BASE;
+	mask = 1 << irq;
 	spin_lock_irqsave(&i8259A_lock, flags);
 	cached_irq_mask |= mask;
 	if (irq & 8)
@@ -68,9 +70,11 @@
 
 void enable_8259A_irq(unsigned int irq)
 {
-	unsigned int mask = ~(1 << irq);
+	unsigned int mask;
 	unsigned long flags;
 
+	irq -= I8259A_IRQ_BASE;
+	mask = ~(1 << irq);
 	spin_lock_irqsave(&i8259A_lock, flags);
 	cached_irq_mask &= mask;
 	if (irq & 8)
@@ -82,10 +86,12 @@
 
 int i8259A_irq_pending(unsigned int irq)
 {
-	unsigned int mask = 1 << irq;
+	unsigned int mask;
 	unsigned long flags;
 	int ret;
 
+	irq -= I8259A_IRQ_BASE;
+	mask = 1 << irq;
 	spin_lock_irqsave(&i8259A_lock, flags);
 	if (irq < 8)
 		ret = inb(PIC_MASTER_CMD) & mask;
@@ -134,9 +140,11 @@
  */
 void mask_and_ack_8259A(unsigned int irq)
 {
-	unsigned int irqmask = 1 << irq;
+	unsigned int irqmask;
 	unsigned long flags;
 
+	irq -= I8259A_IRQ_BASE;
+	irqmask = 1 << irq;
 	spin_lock_irqsave(&i8259A_lock, flags);
 	/*
 	 * Lightweight spurious IRQ detection. We do not want
@@ -322,8 +330,8 @@
 
 	init_8259A(0);
 
-	for (i = 0; i < 16; i++)
+	for (i = I8259A_IRQ_BASE; i < I8259A_IRQ_BASE + 16; i++)
 		set_irq_chip_and_handler(i, &i8259A_chip, handle_level_irq);
 
-	setup_irq(PIC_CASCADE_IR, &irq2);
+	setup_irq(I8259A_IRQ_BASE + PIC_CASCADE_IR, &irq2);
 }