Refactoring result codes (#731)

* refactoring result codes

- Add a main enum who can handle some orphalin result codes and the default `ResultCode.Success` one.
- Add sub-enum by services when it's needed.
- Remove some empty line.
- Recast all service calls to ResultCode.
- Remove some unneeded static declaration.
- Delete unused `NvHelper` class.

* NvResult is back

* Fix

Ryujinx.HLE/HOS/Services/FspSrv/ResultCode.cs

@@ -0,0 +1,16 @@
+namespace Ryujinx.HLE.HOS.Services.FspSrv
+{
+    enum ResultCode
+    {
+        ModuleId       = 2,
+        ErrorCodeShift = 9,
+
+        Success = 0,
+
+        PathDoesNotExist  = (1    << ErrorCodeShift) | ModuleId,
+        PathAlreadyExists = (2    << ErrorCodeShift) | ModuleId,
+        PathAlreadyInUse  = (7    << ErrorCodeShift) | ModuleId,
+        PartitionNotFound = (1001 << ErrorCodeShift) | ModuleId,
+        InvalidInput      = (6001 << ErrorCodeShift) | ModuleId
+    }
+}