ARM: imx: support arm power off in cpuidle for i.mx6sx

This patch introduces an independent cpuidle driver for
i.MX6SX, and supports arm power off in idle, totally
3 levels of cpuidle are supported as below:

1. ARM WFI;
2. SOC in WAIT mode;
3. SOC in WAIT mode + ARM power off.

ARM power off can save at least 5mW power.

This patch also replaces imx6q_enable_rbc with imx6_enable_rbc.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

diff --cc arch/arm/mach-imx/Makefile
Simple merge

diff --cc arch/arm/mach-imx/common.h
Simple merge

diff --cc arch/arm/mach-imx/cpuidle-imx6sx.c
Simple merge

diff --cc arch/arm/mach-imx/cpuidle.h
Simple merge

diff --cc arch/arm/mach-imx/gpc.c
Simple merge

diff --cc arch/arm/mach-imx/mach-imx6sx.c
Simple merge

diff --cc arch/arm/mach-imx/pm-imx6.c
Simple merge