[bsp/renesas][drivers] Fix SCI SPI runtime configuration and transfer errors

[CYFS3]

拉取/合并请求描述：(PR description)

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为什么提交这份PR (why to submit this PR)

在 RZ/N2L EtherKit 的 SCI SPI 回环排查中发现，共享 SCI SPI 驱动存在以下问题：RZ 分频接口将 false 作为分频结果指针传入，且未使用 FSP 配置中的实际时钟源；运行时配置没有可靠地传递给 FSP，重复配置也未正确关闭旧实例；配置过程将 RT-Thread 的位宽从 bit 改成 byte；收发等待超时或出错后仍返回传输长度，导致调用方误判传输成功。

你的解决方案是什么 (what is your solution)

为每条 SCI 总线保存持久的可写 FSP 配置及扩展配置副本，修正各 SCI 分支的分频调用，并在 RZ 分支使用实际配置的时钟源；检查分频错误，在重新配置前显式关闭已打开的实例。保持 RT-Thread 位宽单位为 bit，同步主从模式、时钟极性/相位、位序和回调上下文，保留无片选及无效 CS 引脚保护。

统一处理发送、接收和全双工传输的等待结果，在超时或错误时关闭传输、清理事件和总线归属，使后续操作可以重新配置并重试。

已通过 RZ、普通 SCI、SCI_B 三条分支的主机模拟测试，覆盖 6 档时钟、1～512 字节收发、配置生命周期、多总线隔离及错误恢复

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

• BSP:

• .config:

• action:

]

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clang-format 源码格式化工具确保格式符合RT-Thread代码规范 This PR has been formatted with clang-format and 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

[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).

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🛠 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

• Use workflow from 保持默认分支（通常为 master）
  Keep the default branch (usually master) in Use workflow from
• 在 branch 输入框填写 PR 分支 fix/renesas-sci-spi-runtime
  Enter PR branch fix/renesas-sci-spi-runtime in the branch field
• 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 "/")

3. 等待工作流完成 | Wait for the workflow to complete
   格式化后的代码将作为独立提交推送至你的分支。
   The formatting changes will be pushed to your branch as a separate commit.

完成后，提交将自动更新至 fix/renesas-sci-spi-runtime 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the fix/renesas-sci-spi-runtime 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: bsp_renesas

Reviewers: @kurisaW

Changed Files (Click to expand)

• bsp/renesas/libraries/HAL_Drivers/drivers/drv_sci.c

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📊 Current Review Status (Last Updated: 2026-09-09 17:25 CST)

• ⌛ @kurisaW Pending Review

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📝 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.

[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• renesas-ra2l1