net/mlx5e: Fix static checker warning of potential pointer math issue

Cited patch have an issue in WARN_ON_ONCE check, with wrong address ranges
are compared. Fix that by changing pointer types from u64* to void*. This
will also make code simpler to read.

In addition mlx5e_hv_vhca_fill_ring_stats can get void pointer, so remove
the unnecessary casting when calling it.

Found by static checker:
drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c:41 mlx5e_hv_vhca_fill_stats()
warn: potential pointer math issue ('buf' is a u64 pointer)

Fixes: cef35af3 ("net/mlx5e: Add mlx5e HV VHCA stats agent")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en/hv_vhca_stats.c

@@ -30,22 +30,21 @@ mlx5e_hv_vhca_fill_ring_stats(struct mlx5e_priv *priv, int ch,
 	}
 }
 
-static void mlx5e_hv_vhca_fill_stats(struct mlx5e_priv *priv, u64 *data,
+static void mlx5e_hv_vhca_fill_stats(struct mlx5e_priv *priv, void *data,
 				     int buf_len)
 {
 	int ch, i = 0;
 
 	for (ch = 0; ch < priv->max_nch; ch++) {
-		u64 *buf = data + i;
+		void *buf = data + i;
 
 		if (WARN_ON_ONCE(buf +
 				 sizeof(struct mlx5e_hv_vhca_per_ring_stats) >
 				 data + buf_len))
 			return;
 
-		mlx5e_hv_vhca_fill_ring_stats(priv, ch,
-					      (struct mlx5e_hv_vhca_per_ring_stats *)buf);
-		i += sizeof(struct mlx5e_hv_vhca_per_ring_stats) / sizeof(u64);
+		mlx5e_hv_vhca_fill_ring_stats(priv, ch, buf);
+		i += sizeof(struct mlx5e_hv_vhca_per_ring_stats);
 	}
 }