docs-rst: convert usb docbooks to ReST

As we're moving out of DocBook, let's convert the remaining
USB docbooks to ReST.

The transformation itself on this patch is a no-brainer
conversion using pandoc via this script:
	Documentation/sphinx/tmplcvt
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/DocBook/Makefile

@@ -8,12 +8,11 @@
 
 DOCBOOKS := z8530book.xml  \
 	    kernel-hacking.xml kernel-locking.xml \
-	    writing_usb_driver.xml networking.xml \
+	    networking.xml \
 	    filesystems.xml lsm.xml kgdb.xml \
-	    gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
+	    libata.xml mtdnand.xml librs.xml rapidio.xml \
 	    s390-drivers.xml scsi.xml \
-	    sh.xml w1.xml \
-	    writing_musb_glue_layer.xml
+	    sh.xml w1.xml
 
 ifeq ($(DOCBOOKS),)
 

Documentation/driver-api/index.rst

@@ -26,7 +26,7 @@ available subsections can be seen below.
    regulator
    iio/index
    input
-   usb
+   usb/index
    pci
    spi
    i2c

Documentation/driver-api/usb/index.rst

+=============
+Linux USB API
+=============
+
+.. toctree::
+
+   usb
+   gadget
+   writing_usb_driver
+   writing_musb_glue_layer
+
+.. only::  subproject and html
+
+   Indices
+   =======
+
+   * :ref:`genindex`