SPI controllers may need to be properly setup before chip selects
can be used. Therefore, wait until the spi controller has a chance
to perform their setup procedure before trying to use the chip
select.

This also insures that the chip selects pins are in a good
state before asseting them which otherwise may cause confusion.
Signed-off-by: NFranklin S Cooper Jr <fcooper@ti.com>
Tested-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Tested-by: NIvan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Signed-off-by: NMark Brown <broonie@kernel.org>