docs: driver-api: add a series of orphaned documents

There are lots of documents under Documentation/*.txt and a few other
orphan documents elsehwere that belong to the driver-API book.

Move them to their right place.

Reviewed-by: Cornelia Huck <cohuck@redhat.com> # vfio-related parts
Acked-by: Logan Gunthorpe <logang@deltatee.com> # switchtec
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/ABI/testing/sysfs-class-switchtec

@@ -1,6 +1,6 @@
 switchtec - Microsemi Switchtec PCI Switch Management Endpoint
 
-For details on this subsystem look at Documentation/switchtec.txt.
+For details on this subsystem look at Documentation/driver-api/switchtec.rst.
 
 What: 		/sys/class/switchtec
 Date:		05-Jan-2017