[SCSI] megaraid_sas: fix a bug for 64 bit arches

On 64 bit then -1UL and -1U are not equal, so these conditions don't
work as intended and it breaks error handling.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Sumit Saxena <sumit.saxena@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>