[style][components/fal_rtt] misrac style

[O-O-BOOK]

[
为什么提交这份PR (why to submit this PR)

在 RT-Thread 的 FAL（Flash Abstraction Layer）相关实现中，
部分代码存在在条件判断中直接进行赋值的写法，例如：

if ((fal_flash = fal_flash_device_find(...)) == NULL)

虽然该写法在功能上是正确的，但可读性较差，
并且在代码维护、review 以及静态代码分析场景下容易引起歧义。

本 PR 对上述写法进行了重构，旨在提升代码可读性、可维护性，
并降低后续维护和分析的理解成本。

你的解决方案是什么 (what is your solution)

本 PR 通过将“函数返回值赋值”和“条件判断”进行拆分，
使代码逻辑更加清晰、直观，具体包括：

• 将 flash 设备和分区的查找操作与条件判断分离
• 明确区分设备查找成功和失败的处理路径
• 优化 fal shell 命令中 flash 设备与分区探测逻辑
• 保持现有功能行为不变，仅改善代码结构和可读性

本次修改不引入新功能，也不改变现有接口及运行行为。

请提供验证的 bsp 和 config (provide the config and bsp)

本 PR 未涉及 BSP 或配置项的修改。

BSP：未更改
.config：无更改
action：无

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[github-actions]

👋 感谢您对 RT-Thread 的贡献！Thank you for your contribution to RT-Thread!

为确保代码符合 RT-Thread 的编码规范，请在你的仓库中执行以下步骤运行代码格式化工作流（如果格式化CI运行失败）。
To ensure your code complies with RT-Thread's coding style, please run the code formatting workflow by following the steps below (If the formatting of CI fails to run).

---

🛠 操作步骤 | Steps

1. 前往 Actions 页面 | Go to the Actions page
   点击进入工作流 → | Click to open workflow →

2. 点击 Run workflow | Click Run workflow

• 设置需排除的文件/目录（目录请以"/"结尾）
  Set files/directories to exclude (directories should end with "/")
• 将目标分支设置为 \ Set the target branch to：_fal_rtt
• 设置PR number为 \ Set the PR number to：11178

3. 等待工作流完成 | Wait for the workflow to complete
   格式化后的代码将自动推送至你的分支。
   The formatted code will be automatically pushed to your branch.

完成后，提交将自动更新至 _fal_rtt 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the _fal_rtt branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们，再次感谢您的贡献！💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

[github-actions]

📌 Code Review Assignment

🏷️ Tag: components

Reviewers: @Maihuanyi

Changed Files (Click to expand)

• components/fal/src/fal_rtt.c

🏷️ Tag: components_fal

Reviewers: @illustriousness

Changed Files (Click to expand)

• components/fal/src/fal_rtt.c

---

📊 Current Review Status (Last Updated: 2026-02-06 17:19 CST)

• ⌛ @Maihuanyi Pending Review
• ⌛ @illustriousness Pending Review

---

📝 Review Instructions

1. 维护者可以通过单击此处来刷新审查状态: 🔄 刷新状态
   Maintainers can refresh the review status by clicking here: 🔄 Refresh Status

2. 确认审核通过后评论 LGTM/lgtm
   Comment LGTM/lgtm after confirming approval

3. PR合并前需至少一位维护者确认
   PR must be confirmed by at least one maintainer before merging

ℹ️ 刷新CI状态操作需要具备仓库写入权限。
ℹ️ Refresh CI status operation requires repository Write permission.

[illustriousness]

lgtm

[illustriousness]

请作者点进去签署一下cla 感谢为rt thread贡献代码