cmd/compile/internal/gc: remove atoi function (minor cleanup)

Change-Id: I0ad7836c0e8d70ffdc458e125d97b01e85d8a608
Reviewed-on: https://go-review.googlesource.com/16130Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/esc.go

@@ -7,6 +7,7 @@ package gc
 import (
 	"cmd/internal/obj"
 	"fmt"
+	"strconv"
 	"strings"
 )
 
@@ -1124,7 +1125,8 @@ func parsetag(note *string) uint16 {
 	if note == nil || !strings.HasPrefix(*note, "esc:") {
 		return EscUnknown
 	}
-	em := uint16(atoi((*note)[4:]))
+	n, _ := strconv.ParseInt((*note)[4:], 0, 0)
+	em := uint16(n)
 	if em == 0 {
 		return EscNone
 	}

src/cmd/compile/internal/gc/util.go

@@ -4,19 +4,12 @@ import (
 	"os"
 	"runtime"
 	"runtime/pprof"
-	"strconv"
 )
 
 func (n *Node) Line() string {
 	return Ctxt.LineHist.LineString(int(n.Lineno))
 }
 
-func atoi(s string) int {
-	// NOTE: Not strconv.Atoi, accepts hex and octal prefixes.
-	n, _ := strconv.ParseInt(s, 0, 0)
-	return int(n)
-}
-
 var atExitFuncs []func()
 
 func AtExit(f func()) {