Fix non-portable path warning (pytorch#129474)

MacOS uses case-insensitive filesystem by default, but it's better to specify include path using proper capitalization

Should fix
```
MultiTensorApply.h:4:10: warning: non-portable path to file '<ATen/native/mps/operations/FusedOptimizerOps.h>'; specified path differs in case from file name on disk [-Wnonportable-include-path]
#include <Aten/native/mps/operations/FusedOptimizerOps.h>
```

Pull Request resolved: pytorch#129474
Approved by: https://github.com/albanD, https://github.com/atalman, https://github.com/qqaatw

aten/src/ATen/native/mps/operations/MultiTensorApply.h

@@ -1,7 +1,7 @@
 #pragma once
 #include <ATen/core/Tensor.h>
 #include <ATen/mps/MPSProfiler.h>
-#include <Aten/native/mps/operations/FusedOptimizerOps.h>
+#include <ATen/native/mps/operations/FusedOptimizerOps.h>
 
 namespace at::native {
 namespace mps {
@@ -187,4 +187,4 @@ static void multi_tensor_apply_for_fused_adam(
 }
 
 } // namespace mps
-} // namespace at::native
+} // namespace at::native