scsi: docs: include SCSI Transport SRP diagram at the doc body

Instead of having a separate makefile, and be alone, group
it at the SCSI documentation and make it being built as part
of docs makefile.

Link: https://lore.kernel.org/r/419c455fb40c9a1e85cc9a654a7fdb07aeeccf71.1583136624.git.mchehab+huawei@kernel.orgSigned-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Documentation/scsi/index.rst

@@ -7,4 +7,4 @@ Linux SCSI Subsystem
 .. toctree::
    :maxdepth: 1
 
-
+   scsi_transport_srp/figures

Documentation/scsi/scsi_transport_srp/Makefile

-all: rport_state_diagram.svg rport_state_diagram.png
-
-rport_state_diagram.svg: rport_state_diagram.dot
-	dot -Tsvg -o $@ $<
-
-rport_state_diagram.png: rport_state_diagram.dot
-	dot -Tpng -o $@ $<

Documentation/scsi/scsi_transport_srp/figures.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+SCSI RDMA (SRP) transport class diagram
+=======================================
+
+.. kernel-figure:: rport_state_diagram.dot