doc: prettify OPAL_SYNC_HOST_REBOOT

Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

doc/opal-api/opal-sync-host-reboot-87.rst

@@ -1,22 +1,25 @@
+.. _OPAL_SYNC_HOST_REBOOT:
+
 OPAL_SYNC_HOST_REBOOT
 =====================
-::
 
-   static int64_t opal_sync_host_reboot(void)
+.. code-block:: c
+
+   #define OPAL_SYNC_HOST_REBOOT			87
+
+   static int64_t opal_sync_host_reboot(void);
 
 This OPAL call halts asynchronous operations in preparation for something
 like kexec. It will halt DMA as well notification of some events (such
 as a new error log being available for retreival).
 
-It's meant to be called in a loop until OPAL_SUCCESS is returned.
+It's meant to be called in a loop until :ref:`OPAL_SUCCESS` is returned.
 
 Returns
 -------
-OPAL_SUCCESS
+:ref:`OPAL_SUCCESS`
   Success!
-
-OPAL_BUSY_EVENT
+:ref:`OPAL_BUSY_EVENT`
   not yet complete, call opal_sync_host_reboot() again, possibly with a short delay.
-
-OPAL_BUSY
+:ref:`OPAL_BUSY`
   Call opal_poll_events() and then retry opal_sync_host_reboot