Add timer to reboot RPC for NRF lighting example (#6892)

Add a timer to reboot after the RPC returns, this ensures the host
code knows the RPC command was succesfully recieved before the
device reboots.

Also reboot after doing a FDR.

examples/lighting-app/nrfconnect/README.md

@@ -358,11 +358,11 @@ Semiconductor's kit you own.
 
 ### Building with Pigweed RPCs
 
-The RPCs in `lighting-common/pigweed-lighting.proto` can be used to control
-various functionalities of the lighting app from a USB-connected host computer.
-To build the example with the RPC server, run the following command with
-_build-target_ replaced with the build target name of the Nordic Semiconductor's
-kit you own:
+The RPCs in `lighting-common/lighting_service/lighting_service.proto` can be
+used to control various functionalities of the lighting app from a USB-connected
+host computer. To build the example with the RPC server, run the following
+command with _build-target_ replaced with the build target name of the Nordic
+Semiconductor's kit you own:
 
     $ west build -b build-target -- -DOVERLAY_CONFIG=rpc.overlay
 

examples/lighting-app/nrfconnect/main/Rpc.cpp

@@ -41,6 +41,16 @@ LOG_MODULE_DECLARE(app);
 namespace chip {
 namespace rpc {
 
+namespace {
+
+void reboot_timer_handler(struct k_timer * dummy)
+{
+    NVIC_SystemReset();
+}
+K_TIMER_DEFINE(reboot_timer, reboot_timer_handler, NULL);
+
+} // namespace
+
 class Lighting final : public generated::Lighting<Lighting>
 {
 public:
@@ -75,12 +85,13 @@ class Device final : public generated::Device<Device>
     {
         // TODO: Clear data from KVS
         DeviceLayer::ConfigurationMgr().InitiateFactoryReset();
+        // Reboot device after clearing data
+        k_timer_start(&reboot_timer, K_SECONDS(1), K_FOREVER);
         return pw::OkStatus();
     }
     pw::Status Reboot(ServerContext & ctx, const pw_protobuf_Empty & request, pw_protobuf_Empty & response)
     {
-        NVIC_SystemReset();
-        // WILL NOT RETURN
+        k_timer_start(&reboot_timer, K_SECONDS(1), K_FOREVER);
         return pw::OkStatus();
     }
     pw::Status TriggerOta(ServerContext & ctx, const pw_protobuf_Empty & request, pw_protobuf_Empty & response)