Add missing include to math_utils.hpp

[antonwolfy]

The PR proposes to add missing sycl/sycl.hpp include to math_utils.hpp header file, because sycl::half type and functions from sycl namespace are used there.
Otherwise the isolated include, like

#pragma once

#include <complex>
#include <pybind11/numpy.h>
#include <pybind11/pybind11.h>

#include "utils/math_utils.hpp"

// ... some code

used by an extension code will produce compilation errors:

math_utils.hpp:121:24: error: no member named 'log' in namespace 'sycl'; did you mean simply 'log'?
math_utils.hpp:130:31: error: no member named 'log1p' in namespace 'sycl'; did you mean simply 'log1p'?
...

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[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_239 ran successfully.
Passed: 894
Failed: 1
Skipped: 119

[github-actions]

Array API standard conformance tests for dpctl=0.19.0dev0=py310hdf72452_240 ran successfully.
Passed: 895
Failed: 0
Skipped: 119

[coveralls]

coverage: 87.725%. remained the same
when pulling 7d5acfb on add-missing-include
into 29ee329 on master.

[antonwolfy]

Seems the issue in internal CI doesn't relate to that PR.

[oleksandr-pavlyk]

Thank you @antonwolfy