cpuidle workaround
requested to merge martin.kepplinger/linux-next:i/next-20190607/cpuidle_workaround into imx8-linux-next-devkit
Apply the current workaround by NXP to enable the "cpu-sleep" C-state for cpuidle to use. See https://lkml.org/lkml/2019/6/10/350
This needs u-boot built using the corresponding ATF changes: trusted-firmware-a!2 (merged)