scsi: doc: remove reference to tmscsim.txt file

The tmscsim.txt doc file was removed in c121107d.

Fixes: c121107d

 ("scsi: documentation: Obsolete documentation references")
Signed-off-by: Otto Sabart <ottosabart@seberm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>