scsi: libcxgbi: Remove unnecessary NULL checks for 'tdata' pointer

'tdata' pointer will never be NULL so remove NULL checks.

Link: https://lore.kernel.org/r/1595505391-3335-1-git-send-email-varun@chelsio.com


Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>