add s390x arch build info at the netlink_deprecated_linux bridge driver

Signed-off-by: Jordi Massaguer Pla <jmassaguerpla@suse.de>

libnetwork/drivers/bridge/netlink_deprecated_linux_notarm.go

@@ -1,4 +1,4 @@
-// +build !arm,!ppc64,!ppc64le
+// +build !arm,!ppc64,!ppc64le,!s390x
 
 package bridge
 

libnetwork/drivers/bridge/netlink_deprecated_linux_s390x.go

@@ -0,0 +1,7 @@
+// +build s390x
+
+package bridge
+
+func ifrDataByte(b byte) uint8 {
+	return uint8(b)
+}