unix/linux: update to Go 1.18rc1

The change in ztypes_linux_s390x.go is likely due to CL 350159.

Change-Id: Ib7080255f357d484ee708e128ac9a7ab408a6dc5
Reviewed-on: https://go-review.googlesource.com/c/sys/+/386955
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/unix/ztypes_linux_s390x.go b/unix/ztypes_linux_s390x.go
index 6358806..c426c35 100644
--- a/unix/ztypes_linux_s390x.go
+++ b/unix/ztypes_linux_s390x.go
@@ -210,8 +210,8 @@
 }
 
 type PtracePer struct {
-	_             [0]uint64
-	_             [32]byte
+	Control_regs  [3]uint64
+	_             [8]byte
 	Starting_addr uint64
 	Ending_addr   uint64
 	Perc_atmid    uint16