[ARM] 3064/1: start using ixp2000_reg_wrb

Patch from Lennert Buytenhek

Switch the users of ixp2000_reg_write that depend on writes being
flushed out of the write buffer by the time that function returns
over to ixp2000_reg_wrb.

When using XCB=101, writes to the same functional unit are still
guaranteed to complete in order, so we only need to protect against:
- reordering of writes to different functional units
- masking an interrupt and then reenabling the IRQ bit in CPSR

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-ixp2000/ixdp2x01.c b/arch/arm/mach-ixp2000/ixdp2x01.c
index fee1d7b..dfaaa2d 100644
--- a/arch/arm/mach-ixp2000/ixdp2x01.c
+++ b/arch/arm/mach-ixp2000/ixdp2x01.c
@@ -51,7 +51,7 @@
  *************************************************************************/
 static void ixdp2x01_irq_mask(unsigned int irq)
 {
-	ixp2000_reg_write(IXDP2X01_INT_MASK_SET_REG,
+	ixp2000_reg_wrb(IXDP2X01_INT_MASK_SET_REG,
 				IXP2000_BOARD_IRQ_MASK(irq));
 }
 
@@ -114,7 +114,7 @@
 
 	/* Mask all interrupts from CPLD, disable simulation */
 	ixp2000_reg_write(IXDP2X01_INT_MASK_SET_REG, 0xffffffff);
-	ixp2000_reg_write(IXDP2X01_INT_SIM_REG, 0);
+	ixp2000_reg_wrb(IXDP2X01_INT_SIM_REG, 0);
 
 	for (irq = NR_IXP2000_IRQS; irq < NR_IXDP2X01_IRQS; irq++) {
 		if (irq & valid_irq_mask) {
@@ -316,7 +316,7 @@
 
 static unsigned long ixdp2x01_flash_bank_setup(unsigned long ofs)
 {
-	ixp2000_reg_write(IXDP2X01_CPLD_FLASH_REG,
+	ixp2000_reg_wrb(IXDP2X01_CPLD_FLASH_REG,
 		((ofs >> IXDP2X01_FLASH_WINDOW_BITS) | IXDP2X01_CPLD_FLASH_INTERN));
 	return (ofs & IXDP2X01_FLASH_WINDOW_MASK);
 }
@@ -363,7 +363,7 @@
 
 static void __init ixdp2x01_init_machine(void)
 {
-	ixp2000_reg_write(IXDP2X01_CPLD_FLASH_REG,
+	ixp2000_reg_wrb(IXDP2X01_CPLD_FLASH_REG,
 		(IXDP2X01_CPLD_FLASH_BANK_MASK | IXDP2X01_CPLD_FLASH_INTERN));
 	
 	ixdp2x01_flash_data.nr_banks =