Modify the toolchain path

Author: rcitach

bsp/xuantie/virt64/c906/README.md

@@ -38,7 +38,7 @@ Codename:       noble
 
 ### 2.1. Installing the toolchain
 
-- Compiler: [Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2-20250410.tar.gz](https://www.xrvm.cn/community/download?id=4433353576298909696)
+- Compiler: [Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2-20250410.tar.gz](https://github.com/RT-Thread/toolchains-ci/releases/download/v1.9/Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2.tar.gz)
 - Emulator: [Xuantie-qemu-x86_64-Ubuntu-20.04-V5.0.5-B20250108-0335.tar.gz](https://www.xrvm.cn/community/download?id=4397435198627713024)
 
 Note: If the emulator in the above link does not work, you can compile the emulator using the following repository
@@ -52,7 +52,7 @@ There are three environment variables related to the RT-Thread toolchain
 - `RTT_CC_PREFIX`: is the toolchain prefix, in this case `"riscv64-unknown-elf-"` for the Standard Edition and `"riscv64-unknown-linux-musl-"` for the Smart Edition.
 - `RTT_EXEC_PATH`: the path to the bin folder of the toolchain, e.g. `"$HOME/tools/Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2/bin"`, this is based on the path of the toolchain that was downloaded and unpacked by the user. Thread Standard and Smart versions are two different toolchains, and the path name of `RTT_EXEC_PATH` should be set to `bin`.
 
->Note: This may vary for different toolchains `RTT_CC_PREFIX`, which can be viewed in the toolchain bin folder path.  
+>Note: This may vary for different toolchains `RTT_CC_PREFIX`, which can be viewed in the toolchain bin folder path.
 It is recommended to export these three environment variables in the `.bashrc` file if you use them all the time.
 
 ### 2.3. Downloading the kernel

bsp/xuantie/virt64/c906/README_cn.md

@@ -39,7 +39,7 @@ Codename:       noble
 
 ### 2.1. 安装工具链
 
-- 编译器： [Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2-20250410.tar.gz](https://www.xrvm.cn/community/download?id=4433353576298909696)
+- 编译器： [Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2-20250410.tar.gz](https://github.com/RT-Thread/toolchains-ci/releases/download/v1.9/Xuantie-900-gcc-linux-6.6.0-musl64-x86_64-V3.0.2.tar.gz)
 - 模拟器： [Xuantie-qemu-x86_64-Ubuntu-20.04-V5.0.5-B20250108-0335.tar.gz](https://www.xrvm.cn/community/download?id=4397435198627713024)
 
 注：若上述链接中的模拟器不能使用，可以使用下述仓库编译模拟器