tools/stackusage.py: use toolchain binaries instead of Python libraries

Replace pyelftools and capstone Python library dependencies with
subprocess calls to standard toolchain binaries (readelf, objdump,
addr2line). This eliminates all external Python package requirements,
removes manual DWARF parsing, and reduces the code from 818 to 563
lines.

Works with both GNU and LLVM toolchains via the -p/--prefix option:
  -p arm-none-eabi-  (GCC cross-compiler)
  -p llvm-           (LLVM/clang toolchain)

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

Kconfig

@@ -2631,7 +2631,7 @@ config STACK_USAGE
 	---help---
 		Generate an extra file that specifies the maximum amount of stack used,
 		on a per-function basis. Please use https://github.com/HBehrens/puncover
-		or tools/showstack.sh to generate the more useful report.
+		to generate the more useful report.
 
 config STACK_USAGE_WARNING
 	int "Detect use of large stack variables"

tools/showstack.sh

@@ -1,47 +0,0 @@
-#!/usr/bin/env bash
-############################################################################
-# tools/showstack.sh
-#
-# SPDX-License-Identifier: Apache-2.0
-#
-# Licensed to the Apache Software Foundation (ASF) under one or more
-# contributor license agreements.  See the NOTICE file distributed with
-# this work for additional information regarding copyright ownership.  The
-# ASF licenses this file to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance with the
-# License.  You may obtain a copy of the License at
-#
-#   http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
-# License for the specific language governing permissions and limitations
-# under the License.
-#
-############################################################################
-
-function analyse()
-{
-  sufiles=$(find $1 -name "*.su")
-  if [[ $sufiles != "" ]]
-  then
-    echo $sufiles | xargs -n1 cat | awk -F'\t' '{print $2", "$1}' | sort -n -r | head -n $2
-  fi
-}
-
-if [[ $# == 0 ]]; then
-  echo "usage: $0 <rank> <dir>..."
-  exit
-fi
-
-rank=20
-
-if [[ "$1" =~ ^[0-9]+$ ]]; then
-  rank=$1
-  shift
-fi
-
-for dir in $@; do
-  analyse $dir $rank
-done