Horizon: Implement arp:r and arp:w services (#5802)

* Horizon: Implement arp:r and arp:w services

* Fix formatting

* Remove HLE arp services

* Revert "Remove HLE arp services"

This reverts commit c576fcccadb963db56b96bacabd1c1ac7abfb1ab.

* Keep LibHac impl since it's used in bcat

* Addresses gdkchan's feedback

* ArpApi in PrepoIpcServer and remove LmApi

* Fix 2

* Fixes ArpApi init

* Fix encoding

* Update PrepoService.cs

* Fix prepo

1 files changed, 25 insertions, 0 deletions

diff --git a/src/Ryujinx.Horizon/Arp/Ipc/UnregistrationNotifier.cs b/src/Ryujinx.Horizon/Arp/Ipc/UnregistrationNotifier.cs
new file mode 100644
index 00000000..49f2b1cc
--- /dev/null
+++ b/src/Ryujinx.Horizon/Arp/Ipc/UnregistrationNotifier.cs
@@ -0,0 +1,25 @@
+using Ryujinx.Horizon.Common;
+using Ryujinx.Horizon.Sdk.Arp;
+using Ryujinx.Horizon.Sdk.Arp.Detail;
+using Ryujinx.Horizon.Sdk.Sf;
+
+namespace Ryujinx.Horizon.Arp.Ipc
+{
+    partial class UnregistrationNotifier : IUnregistrationNotifier, IServiceObject
+    {
+        private readonly ApplicationInstanceManager _applicationInstanceManager;
+
+        public UnregistrationNotifier(ApplicationInstanceManager applicationInstanceManager)
+        {
+            _applicationInstanceManager = applicationInstanceManager;
+        }
+
+        [CmifCommand(0)]
+        public Result GetReadableHandle([CopyHandle] out int readableHandle)
+        {
+            readableHandle = _applicationInstanceManager.EventHandle;
+
+            return Result.Success;
+        }
+    }
+}