moby: enable modem-power

hosts/modules/hal/pine64/kernel.nix

@@ -42,6 +42,7 @@ in
       usePmosConfig = true;
       withNixpkgsConfig = true;
       withFullConfig = false;
+      withModemPower = true;
     });
 
     # nixpkgs.hostPlatform.linux-kernel becomes stdenv.hostPlatform.linux-kernel

pkgs/additional/linux-armbian/default.nix

@@ -10,6 +10,7 @@
   usePmosConfig ? true,
   withNixpkgsConfig ? true,
   withFullConfig ? false,
+  withModemPower ? true,
   #VVV nixpkgs calls `.override` on the kernel to configure additional things, but we don't care about those things
   ...
 }@args:
@@ -378,6 +379,15 @@ linux_latest.override {
         RAID6_PQ_BENCHMARK = no;
       };
     }
+  ] ++ lib.optionals withModemPower [
+    {
+      name = "enable-megi-modem-power";
+      patch = null;
+      extraStructuredConfig = with lib.kernel; {
+        # enable /sys/class/modem-power, a thing specific to Megi's kernel/patches
+        MODEM_POWER = yes;
+      };
+    }
   ] ++ lib.optionals withNixpkgsConfig [
     {
       name = "nixpkgs-config";