cmd/compile/internal/ssa: correct error message for AuxArm64BitField

Change-Id: I2e1f48c02cb5c6e90a9cb894eb3bc330a4c5c4b5
GitHub-Last-Rev: 303d1f8
GitHub-Pull-Request: #67124
Reviewed-on: https://go-review.googlesource.com/c/go/+/582615
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Jorropo <jorropo.pgm@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/compile/internal/ssa/value.go

@@ -139,7 +139,7 @@ func (v *Value) AuxValAndOff() ValAndOff {
 
 func (v *Value) AuxArm64BitField() arm64BitField {
 	if opcodeTable[v.Op].auxType != auxARM64BitField {
-		v.Fatalf("op %s doesn't have a ValAndOff aux field", v.Op)
+		v.Fatalf("op %s doesn't have a ARM64BitField aux field", v.Op)
 	}
 	return arm64BitField(v.AuxInt)
 }