dt-bindings: net: airoha: npu: Add firmware-name property

Add firmware-name property in order to introduce the capability to
specify the firmware names used for 'RiscV core' and 'Data section'
binaries. This patch is needed because NPU firmware binaries are board
specific since they depend on the MediaTek WiFi chip used on the board
(e.g. MT7996 or MT7992) and the WiFi chip version info is not available
in the NPU driver. This is a preliminary patch to enable MT76 NPU
offloading if the Airoha SoC is equipped with MT7996 (Eagle) WiFi chipset.

Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Lorenzo Bianconi <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/devicetree/bindings/net/airoha,en7581-npu.yaml

···
       - const: ba
     minItems: 1
 
+  firmware-name:
+    items:
+      - description: Firmware name of RiscV core
+      - description: Firmware name of Data section
+
 required:
   - compatible
   - reg
···
         memory-region = <&npu_firmware>, <&npu_pkt>, <&npu_txpkt>,
                         <&npu_txbufid>, <&npu_ba>;
         memory-region-names = "firmware", "pkt", "tx-pkt", "tx-bufid", "ba";
+        firmware-name = "airoha/en7581_npu_rv32.bin",
+                        "airoha/en7581_npu_data.bin";
       };
     };