zephyr: Fix an invalid url in file CMakeLists.txt
zephyr: Fix an invalid url in file CMakeLists.txt

Replace https://www.zephyrproject.org/doc/dts/device_tree.html with
http://docs.zephyrproject.org/devices/dts/device_tree.html

Signed-off-by: Ding Tao <07dff04f1a3ec2456623b40cc3a82a04949e5843@qq.com>

ATmobica/mcuboot,tamban01/mcuboot,utzig/mcuboot,utzig/mcuboot,runtimeco/mcuboot,ATmobica/mcuboot,tamban01/mcuboot,ATmobica/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,utzig/mcuboot,tamban01/mcuboot,utzig/mcuboot,utzig/mcuboot,runtimeco/mcuboot,tamban01/mcuboot,tamban01/mcuboot,ATmobica/mcuboot,runtimeco/mcuboot,runtimeco/mcuboot