zephyr: Fix an invalid url in file CMakeLists.txt
Replace with
@@ -33,7 +33,7 @@ endmacro()
# this with a device tree overlay file.
#
# See the Zephyr documentation for more information on DT:
-# https://www.zephyrproject.org/doc/dts/device_tree.html
+# http://docs.zephyrproject.org/devices/dts/device_tree.html
set(DTC_OVERLAY_FILE "${CMAKE_CURRENT_SOURCE_DIR}/dts.overlay")
# Standard Zephyr application boilerplate.
