powerpc/thp: tracing: Hide hugepage events under CONFIG_PPC_BOOK3S_64

The events hugepage_set_pmd, hugepage_set_pud, hugepage_update_pmd and
hugepage_update_pud are only called when CONFIG_PPC_BOOK3S_64 is defined.
As each event can take up to 5K regardless if they are used or not, it's
best not to define them when they are not used. Add #ifdef around these
events when they are not used.

Cc: Masami Hiramatsu <[e-mail]>
Cc: Mathieu Desnoyers <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Acked-by: David Hildenbrand <[e-mail]>
Acked-by: Madhavan Srinivasan <[e-mail]>
Signed-off-by: Steven Rostedt (Google) <[e-mail]>

include/trace/events/thp.h

···
 #include <linux/types.h>
 #include <linux/tracepoint.h>
 
+#ifdef CONFIG_PPC_BOOK3S_64
 DECLARE_EVENT_CLASS(hugepage_set,
 
 	    TP_PROTO(unsigned long addr, unsigned long pte),
···
 	    TP_PROTO(unsigned long addr, unsigned long pud, unsigned long clr, unsigned long set),
 	    TP_ARGS(addr, pud, clr, set)
 );
+#endif /* CONFIG_PPC_BOOK3S_64 */
 
 DECLARE_EVENT_CLASS(migration_pmd,