[ARM] Rename chipdata to 'base' and make it an iomem pointer

In all current use cases, "chipdata" is used to store an iomem address.
Mark it with __iomem, and rename it to 'base'.  Leave the accessor macros
alone.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-at91rm9200/gpio.c b/arch/arm/mach-at91rm9200/gpio.c
index 0e396fe..5ab4627 100644
--- a/arch/arm/mach-at91rm9200/gpio.c
+++ b/arch/arm/mach-at91rm9200/gpio.c
@@ -261,7 +261,7 @@
 	void __iomem	*pio;
 	u32		isr;
 
-	pio = (void __force __iomem *) desc->chipdata;
+	pio = desc->base;
 
 	/* temporarily mask (level sensitive) parent IRQ */
 	desc->chip->ack(irq);
@@ -312,7 +312,7 @@
 		__raw_writel(~0, controller + PIO_IDR);
 
 		set_irq_data(id, (void *) pin);
-		set_irq_chipdata(id, (void __force *) controller);
+		set_irq_chipdata(id, controller);
 
 		for (i = 0; i < 32; i++, pin++) {
 			set_irq_chip(pin, &gpio_irqchip);