rt3200 needs pmsg-size set in its dts for persistent logging

devices/belkin-rt3200/default.nix

@@ -113,7 +113,8 @@
   };
 
   module = {pkgs, config, lib, lim, ... }:
-    let firmware = pkgs.stdenv.mkDerivation {
+    let inherit (lib) mkIf;
+        firmware = pkgs.stdenv.mkDerivation {
           name = "wlan-firmware";
           phases = ["installPhase"];
           installPhase = ''
@@ -268,6 +269,9 @@
             "${openwrt.src}/target/linux/mediatek/dts"
             "${config.system.outputs.kernel.modulesupport}/arch/arm64/boot/dts/mediatek/"
           ];
+          includes = mkIf config.logging.persistent.enable [
+            ./pstore-pmsg.dtsi
+          ];
         };
 
         # - 0x000000000000-0x000008000000 : "spi-nand0"

devices/belkin-rt3200/pstore-pmsg.dtsi

@@ -0,0 +1,8 @@
+/ {
+	reserved-memory {
+		/* make sure address matches upstream  */
+		ramoops@42ff0000 {
+			pmsg-size = <0x10000>;
+		};
+	};
+};