[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/Kconfig b/arch/arm/Kconfig
index 6783c2e..3f48e35 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -233,6 +233,8 @@
 
 config ARCH_IOP13XX
 	bool "IOP13xx-based"
+	depends on MMU
+	select PLAT_IOP
 	select PCI
 	help
 	  Support for Intel's IOP13XX (XScale) family of processors.