mlxsw: spectrum: Make function mlxsw_sp_kvdl_part_occ() static

Fixes the following sparse warning:

drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c:289:5: warning:
 symbol 'mlxsw_sp_kvdl_part_occ' was not declared. Should it be static?
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NArkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c

@@ -286,7 +286,7 @@ static void mlxsw_sp_kvdl_parts_fini(struct mlxsw_sp *mlxsw_sp)
 		mlxsw_sp_kvdl_part_fini(mlxsw_sp, i);
 }
 
-u64 mlxsw_sp_kvdl_part_occ(struct mlxsw_sp_kvdl_part *part)
+static u64 mlxsw_sp_kvdl_part_occ(struct mlxsw_sp_kvdl_part *part)
 {
 	unsigned int nr_entries;
 	int bit = -1;