scsi: docs: Add an empty index file for SCSI documents

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.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/Documentation/index.rst b/Documentation/index.rst
index e99d0bd..d39fd2c 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -130,6 +130,7 @@
    bpf/index
    usb/index
    PCI/index
+   scsi/index
    misc-devices/index
    mic/index
    scheduler/index