om> 1230920198 -0600

[SCSI] libsas: fix test for negative unsigned and typos

unsigned req->data_len cannot be negative, and fix =-/-= typo

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>