cmd/asm/internal/arch: delete unused s390x functions

These functions are not necessary and are not called anywhere.

Change-Id: I1c0d814ba3044c27e3626ac9e6052d8154140404
Reviewed-on: https://go-review.googlesource.com/c/go/+/201697
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/asm/internal/arch/s390x.go

@@ -9,7 +9,6 @@
 package arch
 
 import (
-	"cmd/internal/obj"
 	"cmd/internal/obj/s390x"
 )
 
@@ -59,26 +58,6 @@ func jumpS390x(word string) bool {
 	return false
 }
 
-// IsS390xCMP reports whether the op (as defined by an s390x.A* constant) is
-// one of the CMP instructions that require special handling.
-func IsS390xCMP(op obj.As) bool {
-	switch op {
-	case s390x.ACMP, s390x.ACMPU, s390x.ACMPW, s390x.ACMPWU:
-		return true
-	}
-	return false
-}
-
-// IsS390xNEG reports whether the op (as defined by an s390x.A* constant) is
-// one of the NEG-like instructions that require special handling.
-func IsS390xNEG(op obj.As) bool {
-	switch op {
-	case s390x.ANEG, s390x.ANEGW:
-		return true
-	}
-	return false
-}
-
 func s390xRegisterNumber(name string, n int16) (int16, bool) {
 	switch name {
 	case "AR":