[SCSI] FlashPoint: fix off-by-one errors

This patch fixes off-by-one errors in error checks (the variables are
used as array indexes for arrays with MAX_SCSI_TAR resp. MAX_LUN
elements) spotted by the Coverity checker.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>