[cfi] add autoprobing, use cfi size for flash chips size
If a flash chip has been added with the size of "0" the cfi's size is
used for the flash chip.
Signed-off-by: Karsten Schwinne <kartsten.schwinne@de.bucurus.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>