ARM: dts: remove redundant imx dtb targets from Makefile
We already have CONFIG_ARCH_MXC cover imx5 and imx6 dtb targets.
Remove the redundant ones with CONFIG_ARCH_IMX5 and CONFIG_SOC_IMX6Q.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>