corrected use of src_offset in copy_from_numpy_into_usm_ndarray

When figuring out the bytes-boundary of numpy array to form
the sycl::buffer we use simplified strides and shapes, and hence
must start with src_offset, not with zero.

Now, both of these copy calls correctly populate the destination
usm_ndarray.

```
In [2]: n, m = 10**2, 10**3

In [3]: a = np.hstack((np.arange(n, dtype=np.int32),) * m)

In [4]: b = np.flipud(a)

In [5]:

In [5]: c = dpt.asarray(b, device='cpu')

In [6]: c
Out[6]: usm_ndarray([99, 98, 97, ...,  2,  1,  0], dtype=int32)

In [7]: import dpctl.tensor._tensor_impl as ti

In [8]: c = dpt.empty(b.shape, dtype=b.dtype)[::-1]

In [9]: ti._copy_numpy_ndarray_into_usm_ndarray(src=b, dst=c, sycl_queue=c.sycl_queue)

In [10]: c
Out[10]: usm_ndarray([99, 98, 97, ...,  2,  1,  0], dtype=int32)

In [11]: c = dpt.empty(b.shape, dtype=b.dtype)

In [12]: ti._copy_numpy_ndarray_into_usm_ndarray(src=b, dst=c, sycl_queue=c.sycl_queue)

In [13]: c
Out[13]: usm_ndarray([99, 98, 97, ...,  2,  1,  0], dtype=int32)
```

Author: oleksandr-pavlyk

dpctl/tensor/libtensor/source/copy_numpy_ndarray_into_usm_ndarray.cpp

@@ -211,8 +211,8 @@ void copy_numpy_ndarray_into_usm_ndarray(
     }
 
     // Minumum and maximum element offsets for source np.ndarray
-    py::ssize_t npy_src_min_nelem_offset(0);
-    py::ssize_t npy_src_max_nelem_offset(0);
+    py::ssize_t npy_src_min_nelem_offset(src_offset);
+    py::ssize_t npy_src_max_nelem_offset(src_offset);
     for (int i = 0; i < nd; ++i) {
         if (simplified_src_strides[i] < 0) {
             npy_src_min_nelem_offset +=