fix regression in s390x SO_PEERSEC definition
analogous to commit efda534b212f713fe2b92a62b06e45f656b763ce for
powerpc. commit 587f5a53bc3a68d80b239ba515d583df690a96df moved the
definition of SO_PEERSEC to bits/socket.h for archs where the SO_*
macros differ.
diff --git a/arch/s390x/bits/socket.h b/arch/s390x/bits/socket.h
index 2b81bfe..f2983ee 100644
--- a/arch/s390x/bits/socket.h
+++ b/arch/s390x/bits/socket.h
@@ -38,6 +38,7 @@
#define SO_RCVTIMEO 20
#define SO_SNDTIMEO 21
#define SO_ACCEPTCONN 30
+#define SO_PEERSEC 31
#define SO_SNDBUFFORCE 32
#define SO_RCVBUFFORCE 33
#define SO_PROTOCOL 38