syscall: fix running mkall.sh on linux/{ppc64,ppc64le}

Change-Id: I58c6e914d0e977d5748c87d277e30c933ed86f99
Reviewed-on: https://go-review.googlesource.com/9924Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/syscall/mkall.sh

@@ -285,7 +285,7 @@ esac
 		syscall_goos="syscall_bsd.go $syscall_goos"
  		;;
  	esac
-	if [ -n "$mksyscall" ]; then echo "$mksyscall $syscall_goos syscall_$GOOSARCH.go |gofmt >zsyscall_$GOOSARCH.go"; fi
+	if [ -n "$mksyscall" ]; then echo "$mksyscall $syscall_goos $GOOSARCH_in |gofmt >zsyscall_$GOOSARCH.go"; fi
 	if [ -n "$mksysctl" ]; then echo "$mksysctl |gofmt >$zsysctl"; fi
 	if [ -n "$mksysnum" ]; then echo "$mksysnum |gofmt >zsysnum_$GOOSARCH.go"; fi
 	if [ -n "$mktypes" ]; then echo "$mktypes types_$GOOS.go |gofmt >ztypes_$GOOSARCH.go"; fi