doc: Sphinxify the tracepoint docbook

Convert the tracepoint docbook template to RST and add it to the core-api
manual.  No changes to the actual text beyond the mechanical formatting
conversion.

Cc: Jason Baron <jbaron@redhat.com>
Cc: William Cohen <wcohen@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/DocBook/Makefile

@@ -12,8 +12,7 @@ DOCBOOKS := z8530book.xml  \
 	    kernel-api.xml filesystems.xml lsm.xml kgdb.xml \
 	    gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
 	    genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
-	    80211.xml sh.xml regulator.xml \
-	    tracepoint.xml w1.xml \
+	    80211.xml sh.xml regulator.xml w1.xml \
 	    writing_musb_glue_layer.xml crypto-API.xml iio.xml
 
 ifeq ($(DOCBOOKS),)