[ARM] 4184/1: iop: cp6 access handler (undef_hook)

Enable svc access to cp6 via an undefined instruction hook.  Do not enable
access for usr code.

This patch also makes iop13xx select PLAT_IOP, this requires a small change
to drivers/i2c/busses/i2c-iop3xx.c.

Per Lennert Buytenhek's note, the cp6 trap routine is moved to arch/arm/plat-iop
Per Nicolas Pitre's note, the cp_wait is skipped since the latency to
return to the faulting function is longer than cp_wait.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-iop13xx/irq.c b/arch/arm/mach-iop13xx/irq.c
index dbbc07c..162b932 100644
--- a/arch/arm/mach-iop13xx/irq.c
+++ b/arch/arm/mach-iop13xx/irq.c
@@ -250,11 +250,14 @@
 	.unmask = iop13xx_irq_unmask3,
 };
 
+extern void iop_init_cp6_handler(void);
+
 void __init iop13xx_init_irq(void)
 {
 	unsigned int i;
 
 	u32 cp_flags = iop13xx_cp6_save();
+	iop_init_cp6_handler();
 
 	/* disable all interrupts */
 	write_intctl_0(0);