ARM: dts: rockchip: support the spi for rk3036

This patch adds the needed spi node for rk3036 dts.

We have to use the 4 bus emmc to work if someone want to support
the spi devices, since the pins are re-used by emmc data[5-8] and spi.
In some caseswe need to support the spi devices, that will waste the
emmc performance.

Moment, the kylin/evb hasn't the spi devices to work, so maybe we need wait
the new required to enable in kylin/evb board.

Anyway, the spi should be needed land in rk3036 dts.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>