dt-bindings: net: airoha: npu: Add memory regions used for wlan offload

dt-bindings: net: airoha: npu: Add memory regions used for wlan offload

Document memory regions used by Airoha EN7581 NPU for wlan traffic
offloading. The brand new added memory regions do not introduce any
backward compatibility issues since they will be used just to offload
traffic to/from the MT76 wireless NIC and the MT76 probing will not fail
if these memory regions are not provide, it will just disable offloading
via the NPU module.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/20250811-airoha-en7581-wlan-offlaod-v7-1-58823603bb4e@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>