providers/mlx5: Correct argument order in calloc call to fix warning

This commit fixes a compiler warning related to the use of calloc.
```
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c: In function ‘__pyx_pf_7pyverbs_9providers_4mlx5_6mlx5dv_10WqeCtrlSeg___init__’:
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c:48608:53: warning: ‘calloc’ sizes specified with ‘sizeof’ in the earlier argument and not in the later argument [-Wcalloc-transposed-args]
48608 |   __pyx_v_self->__pyx_base.segment = calloc((sizeof(struct mlx5_wqe_ctrl_seg)), 1);
      |                                                     ^~~~~~
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c:48608:53: note: earlier argument should specify number of elements, later size of each element
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c: In function ‘__pyx_pf_7pyverbs_9providers_4mlx5_6mlx5dv_10WqeDataSeg___init__’:
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c:50301:53: warning: ‘calloc’ sizes specified with ‘sizeof’ in the earlier argument and not in the later argument [-Wcalloc-transposed-args]
50301 |   __pyx_v_self->__pyx_base.segment = calloc((sizeof(struct mlx5_wqe_data_seg)), 1);
      |                                                     ^~~~~~
rdma-core/build/pyverbs/providers/mlx5/mlx5dv.c:50301:53: note: earlier argument should specify number of elements, later size of each element

```

The warning was due to transposed arguments in the calloc call,
where the number of elements and the size of each element were
specified in the wrong order.

The correct order for calloc's arguments is:
void *calloc(size_t nmemb, size_t size)

Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>

pyverbs/providers/mlx5/mlx5dv.pyx

@@ -1513,7 +1513,7 @@ cdef class WqeCtrlSeg(WqeSeg):
         using mlx5dv_set_ctrl_seg, segment values are accessed
         through the getters/setters.
         """
-        self.segment = calloc(sizeof(dv.mlx5_wqe_ctrl_seg), 1)
+        self.segment = calloc(1, sizeof(dv.mlx5_wqe_ctrl_seg))
         self.set_ctrl_seg(pi, opcode, opmod, qp_num, fm_ce_se, ds, signature, imm)
 
     def __str__(self):
@@ -1584,7 +1584,7 @@ cdef class WqeDataSeg(WqeSeg):
         Create a dv.mlx5_wqe_data_seg by allocating it and using
         dv.mlx5dv_set_data_seg with the values received in init
         """
-        self.segment = calloc(sizeof(dv.mlx5_wqe_data_seg), 1)
+        self.segment = calloc(1, sizeof(dv.mlx5_wqe_data_seg))
         self.set_data_seg(length, lkey, addr)
 
     @staticmethod
@@ -1646,7 +1646,7 @@ cdef class Wqe(PyverbsCM):
             self.is_user_addr = False
             allocation_size = sum(map(lambda x: x.sizeof() if isinstance(x, WqeSeg) else len(x),
                                       self.segments))
-            self.addr = calloc(allocation_size, 1)
+            self.addr = calloc(1, allocation_size)
         addr = <uintptr_t>self.addr
         for seg in self.segments:
             if isinstance(seg, WqeSeg):