zephyr-openthread-rcp: add recipe for OpenThread radio co-processor sample

This builds the sample for the radio co-processor firmware with a specific
set of overlays to work over USB transport.

Signed-off-by: Stefan Schmidt <stefan.schmidt@huawei.com>
Signed-off-by: Naveen Saini <naveen.kumar.saini@intel.com>

meta-zephyr-core/recipes-kernel/zephyr-kernel/zephyr-openthread-rcp.bb

+include zephyr-sample.inc
+
+ZEPHYR_SRC_DIR = "${S}/samples/net/openthread/coprocessor"
+
+EXTRA_OECMAKE += "-DCONF_FILE="prj.conf overlay-rcp.conf overlay-usb-nrf-br.conf" -DDTC_OVERLAY_FILE="usb.overlay""
+
+# The overlay config and OpenThread itself imposes some specific requirements
+# towards the boards (e.g. flash layout and ieee802154 radio) so we need to
+# limit to known working machines here.
+COMPATIBLE_MACHINE = "(arduino-nano-33-ble)"