On the vf610-zii-scu4-aib board there is a hi8435 (32-channel
discrete-to-digital SPI sensor device) in the DSPI0 bus.

Add support for it.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>