We cannot scan two chips for imx23 and imx28:
imx23: the Ready-Busy1 line is not connected for some board.
imx28: we do not set the pinctrl for Ready-Busy1
So we only scan two chips for imx6.
Signed-off-by: Huang Shijie <b32955@freescale.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com>