[Build] QNN EP build : implicit conversion loses integer precision

@adrianlizarraga is already working on this.

Since Oct 5, 2023.

### Describe the issue

When building with use_qnn (clang, targeting Android), several files in the QNN Execution Provider sources use size_t and unit64_t interchangeably. Clang disagrees with that.

base_op_builder.cc - this one is a simple fix, just change line 212 to use auto

simple_op_builder.cc
qnn_backend_manager.cc
- In these files, unt64_t is returned from some functions, but passed as size_t to other methods
```
simple_op_builder.cc:175:68: error: implicit conversion loses integer precision: 'int64_t' (aka 'long long') to 'size_t' (aka 'unsigned int') [-Werror,-Wshorten-64-to-32]
ParQuantizeLinearStd(&tensor_data.alpha, unpacked_data.data(), num_of_elements, scale, zero_point, thread_pool);

qnn_backend_manager.cc:361:87: error: implicit conversion loses integer precision: 'uint64_t' (aka 'unsigned long long') to 'size_t' (aka 'unsigned int') [-Werror,-Wshorten-64-to-32]
std::unique_ptr context_buffer = std::make_unique(required_buffer_size);

qnn_backend_manager.cc:413:66: error: implicit conversion loses integer precision: 'uint64_t' (aka 'unsigned long long') to 'std::streamsize' (aka 'int') [-Werror,-Wshorten-64-to-32]
of_stream.write(reinterpret_cast(context_buffer.get()), written_buffer_size);

qnn_backend_manager.cc:440:79: error: implicit conversion loses integer precision: 'uint64_t' (aka 'unsigned long long') to 'size_t' (aka 'unsigned int') [-Werror,-Wshorten-64-to-32]
std::unique_ptr buffer = std::make_unique(buffer_size);

qnn_backend_manager.cc:444:84: error: implicit conversion loses integer precision: 'uint64_t' (aka 'unsigned long long') to 'std::streamsize' (aka 'int') [-Werror,-Wshorten-64-to-32]
const auto& read_result = cache_file.read(reinterpret_cast(buffer.get()), buffer_size);

### Urgency

_No response_

### Target platform

Android

### Build script

python3 tools/ci_build/build.py \
--cmake_extra_defines "CMAKE_VERBOSE_MAKEFILE=ON" \
--cmake_extra_defines "CMAKE_C_FLAGS=$extra_cflags" \
--cmake_extra_defines "CMAKE_CXX_FLAGS=$extra_cflags" \
--build_dir "$build_dir" \
--config $build_type \
--build_shared_lib \
--parallel \
--android \
--android_abi $build_target \
--android_api $VERSION \
--android_sdk_path "$(get_android_home)" \
--android_ndk_path "[...]" \
--android_cpp_shared \
--use_cache \
--use_xnnpack \
--use_nnapi \
--use_qnn \
--qnn_home="[...]" \
--skip_tests \
--path_to_protoc_exe "$PROTOC" \

### Error / output

(See above)

### Visual Studio Version

_No response_

### GCC / Compiler Version

_No response_