[SCSI] gdth: remove command accessors

These are no longer necessary.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Tested-by: Joerg Dorchain: <joerg@dorchain.net>
Tested-by: Stefan Priebe <s.priebe@allied-internet.ag>
Tested-by: Jon Chelton <jchelton@ffpglobal.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>