zephyr-openthread-rcp: Support nrf52840dk-nrf52840 machine

This Nordic reference design can be a fallback option for
Oniro's gateway-blueprint
I've been tested it myself along my single arduino-nano node

Forwarded: !22
Relate-to: eclipse/oniro-blueprints/transparent-gateway/meta-oniro-blueprints-gateway#6


Signed-off-by: Philippe Coval <philippe.coval.ext@huawei.com>

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

@@ -7,7 +7,7 @@ EXTRA_OECMAKE += "-DCONF_FILE="prj.conf overlay-rcp.conf overlay-usb-nrf-br.conf
 # 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)"
+COMPATIBLE_MACHINE = "(arduino-nano-33-ble|nrf52840dk-nrf52840)"
 
 python __anonymous() {
     has_acm0 = d.getVar("ONIRO_ENABLE_ACM0")