powerpc/trace: Restrict hash_fault trace event to HASH MMU

'perf list' on powerpc 8xx shows an event named "1:hash_fault".

This event is pointless because trace_hash_fault() is called only
from mm/book3s64/hash_utils.c

Only define it when CONFIG_PPC_64S_HASH_MMU is selected.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/85a86e51b4ab26ce4b592984cc0a0851a3cc9479.1708076780.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/trace.h

@@ -267,6 +267,7 @@ TRACE_EVENT_FN(opal_exit,
 );
 #endif
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 TRACE_EVENT(hash_fault,
 
 	    TP_PROTO(unsigned long addr, unsigned long access, unsigned long trap),
@@ -286,7 +287,7 @@ TRACE_EVENT(hash_fault,
 	    TP_printk("hash fault with addr 0x%lx and access = 0x%lx trap = 0x%lx",
 		      __entry->addr, __entry->access, __entry->trap)
 );
-
+#endif
 
 TRACE_EVENT(tlbie,