ARM: dts: fix the chip select gpios definition in the SPI nodes

This patch replaces the "cs-gpio" from "controller-data" node
as was specified in the old binding and uses the standard
"cs-gpios" property expected by the SPI core as is defined now
in the spi-s3c64xx driver DT binding.

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>