In gerenal, the "rockchip,rockchip-spi" string will match the dts
that's great in spi driver. After all the most of rockchip SoCs ar
same spi controller.

Then, we should keep the old style to match the dts various.
Signed-off-by: NCaesar Wang <wxt@rock-chips.com>
Signed-off-by: NMark Brown <broonie@kernel.org>