Only csio_hw_free() calling csio_dfs_destroy() and it is not checking
return value. So remove the return from csio_dfs_destroy().

Link: https://lore.kernel.org/r/20191028194234.GA27848@sauravSigned-off-by: Saurav Girepunje <saurav.girepunje@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>