[bsp/renesas][drivers] Read PWM settings from GPT registers

[CYFS3]

拉取/合并请求描述：(PR description)

[

为什么提交这份PR (why to submit this PR)

Renesas PWM 驱动原先依赖 FSP 静态配置读取周期和占空比，无法准确反映运行时通过 PWM 接口更新后的 GPT 硬件状态。

你的解决方案是什么 (what is your solution)

从 GPT 的周期缓冲寄存器、GTCCR 比较寄存器和 GTUDDTYC 强制输出状态读取实际配置，并使用 R_GPT_InfoGet() 返回的计数时钟进行纳秒换算；设置时同步更新 GTIOCA 和 GTIOCB，并校验 GPT PWM 模式。

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).

---

🛠 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-pwm-driver-upstream
  Enter PR branch fix/renesas-pwm-driver-upstream 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-pwm-driver-upstream 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the fix/renesas-pwm-driver-upstream 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]

MemBrowse Memory Report

No memory changes detected for:

• renesas-ra2l1

[CYFS3]

v5.3.0

[kurisaW]

RZ上辛苦也验证下