scsi: MAINTAINERS: Adjust to reflect gdth scsi driver removal

Commit 0653c358

 ("scsi: Drop gdth driver") fails to update MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains:

  warning: no file matches F:    drivers/scsi/gdt*

Remove the GDT SCSI DISK ARRAY CONTROLLER DRIVER section as well, as the
driver is removed now.

Link: https://lore.kernel.org/r/20210129052829.13642-1-lukas.bulwahn@gmail.com
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>