Preserve chip operation mode if no mode is specified via devicetree. This
enables operation when chip configuration is done by BIOS/ROMMON.
Signed-off-by: NAlexander Koch <mail@alexanderkoch.net>
Acked-by: NMichael Hornung <mhornung.linux@gmail.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>