In preparation for adding the SCSI documents to the documentation
body, add an empty index for it.

The next patches should be adding contents to it, as files get
converted to ReST format.

Link: https://lore.kernel.org/r/4d8c1b7ebe5898ac4a8265ca5e5a9552da3b426f.1583136624.git.mchehab+huawei@kernel.orgSigned-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>