ARM: imx6q: support WAIT mode using cpuidle

Add WAIT mode (ARM core clock gating) support to imx6q cpuidle driver.
As WAIT mode is broken on imx6q TO 1.0 and 1.1, it only enables the
support for revision 1.2 with chicken bit set.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index 27726de..77a3b4b 100644
--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c
@@ -202,7 +202,12 @@
 
 static void __init imx6q_init_late(void)
 {
-	imx6q_cpuidle_init();
+	/*
+	 * WAIT mode is broken on TO 1.0 and 1.1, so there is no point
+	 * to run cpuidle on them.
+	 */
+	if (imx6q_revision() > IMX_CHIP_REVISION_1_1)
+		imx6q_cpuidle_init();
 }
 
 static void __init imx6q_map_io(void)