Some registers on pfuze3000 will lost after exit from LPSR, need restore them,
otherwise system may reboot with below command after system enter LPSR one time:
root@imx7d_all:~# echo enabled > /sys/class/tty/ttymxc0/power/wakeup
root@imx7d_all:~# echo mem > /sys/power/state
because LDOGCTL not recover as 1. Add 'fsl,lpsr-mode' property to this case,
please add this property if your board support LPSR mode as imx7d-12x12-lpddr3-arm2
board.
Signed-off-by: Robin Gong <b38343@freescale.com>