[openwrt/openwrt] firmware: Add support for Airoha EN7581 NPU firmware

[LEDE Commits]

ansuel pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/e00f77b3e7df9b4280b7a161ceb0b267f7ee6bb9

commit e00f77b3e7df9b4280b7a161ceb0b267f7ee6bb9
Author: Christian Marangi <ansuelsmth at gmail.com>
AuthorDate: Mon Sep 1 18:03:35 2025 +0200

    firmware: Add support for Airoha EN7581 NPU firmware
    
    Add support for Airoha EN7581 NPU firmware present in linux-firmware.
    Support for it is fully upstream with the Ethernet part fully pushed and
    the Wireless Offload currently in progress for various WiFi chip.
    
    Link: https://github.com/openwrt/openwrt/pull/19816
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
---
 package/firmware/linux-firmware/airoha.mk | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/package/firmware/linux-firmware/airoha.mk b/package/firmware/linux-firmware/airoha.mk
index 4d46ac5447..a89a1966e4 100644
--- a/package/firmware/linux-firmware/airoha.mk
+++ b/package/firmware/linux-firmware/airoha.mk
@@ -15,3 +15,14 @@ endif
 endef
 
 $(eval $(call BuildPackage,airoha-en8811h-firmware))
+
+Package/airoha-en7581-npu-firmware = $(call Package/firmware-default,Airoha EN7581 NPU firmware,,LICENSE.airoha)
+define Package/airoha-en7581-npu-firmware/install
+	$(INSTALL_DIR) $(1)/lib/firmware/airoha
+	$(CP) \
+		$(PKG_BUILD_DIR)/airoha/en7581_npu_data.bin \
+		$(PKG_BUILD_DIR)/airoha/en7581_npu_rv32.bin \
+		$(1)/lib/firmware/airoha
+endef
+
+$(eval $(call BuildPackage,airoha-en7581-npu-firmware))