Buses sometimes want to pass data to their children when they are probed.
For example, a SPI bus may want to tell the slave device about the chip
select it is connected to.

Add a new function to permit the parent data to be supplied to the child.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Acked-by: NJagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>