don't declare samplers for separate textures

src/Ryujinx.Graphics.Shader/CodeGen/Msl/MslGenerator.cs

@@ -137,9 +137,13 @@ namespace Ryujinx.Graphics.Shader.CodeGen.Msl
                 {
                     var textureTypeName = texture.Type.ToMslTextureType();
                     args = args.Append($"{textureTypeName} tex_{texture.Name} [[texture({texture.Binding})]]").ToArray();
+                    // If the texture is not separate, we need to declare a sampler
+                    if (!texture.Separate)
+                    {
                         args = args.Append($"sampler samp_{texture.Name} [[sampler({texture.Binding})]]").ToArray();
                     }
                 }
+            }
 
             return $"{funcKeyword} {returnType} {funcName ?? function.Name}({string.Join(", ", args)})";
         }