Currently in the case where parse_attr fails to be allocated the memoryApplied to net-next-mlx5
pointed to by attr2 is kfree'd but the non-null pointer attr2 is returned
and a potential use of a kfree'd object can occur. Fix this by returning
NULL to indicate a memory allocation error.
Addresses issue found by clang-scan:
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:3401:3: warning: Use of
memory after it is freed [unix.Malloc]
Fixes: 8300f225268b ("net/mlx5e: Create new flow attr for multi table actions")
Signed-off-by: Colin Ian King <colin.i.king@xxxxxxxxx>