u-boot-rockchip: add DEPENDS for dtc
u-boot-rockchip: add DEPENDS for dtc

The recent "recipe-specific sysroot" change in openembedded-core has caused
the build to be more strict about what tools can be used from the host. As
such it's probably best to use the generated dtc for u-boot.

Signed-off-by: Trevor Woerner <8835777cd84fba3d7873eabbbe1f2de2d3f25b00@gmail.com>

hizukiayaka/meta-rockchip,hizukiayaka/meta-rockchip,twoerner/meta-rockchip-twoerner,hizukiayaka/meta-rockchip,twoerner/meta-rockchip-twoerner