s390/dis: use explicit buf len

Pass buffer length in extra parameter.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kvm/trace.h b/arch/s390/kvm/trace.h
index 2b29e62..53252d2d 100644
--- a/arch/s390/kvm/trace.h
+++ b/arch/s390/kvm/trace.h
@@ -117,7 +117,7 @@
 			   __entry->instruction,
 			   insn_to_mnemonic((unsigned char *)
 					    &__entry->instruction,
-					 __entry->insn) ?
+					 __entry->insn, sizeof(__entry->insn)) ?
 			   "unknown" : __entry->insn)
 	);