broadcom-bt-firmware: revert to unfree

license was misinterpreted, it is now only conditionally in the all
firmware list included, if `allowUnfree` is set.

fixes #25567

nixos/modules/hardware/all-firmware.nix

···
 
   config = mkIf config.hardware.enableAllFirmware {
     hardware.firmware = with pkgs; [
-      broadcom-bt-firmware
       firmwareLinuxNonfree
       intel2200BGFirmware
       rtl8723bs-firmware
       rtl8192su-firmware
+    ] ++ optionals config.nixpkgs.config.allowUnfree [
+      broadcom-bt-firmware
     ];
   };
 

pkgs/os-specific/linux/firmware/broadcom-bt-firmware/default.nix

···
   meta = with stdenv.lib; {
     description = "Firmware for Broadcom WIDCOMM® Bluetooth devices";
     homepage = http://www.catalog.update.microsoft.com/Search.aspx?q=Broadcom+bluetooth;
-    license = licenses.unfreeRedistributableFirmware;
+    license = licenses.unfree;
     platforms = platforms.linux;
     maintainers = with maintainers; [ zraexy ];
   };