tools/Rust: Add support for x86 platform

[no1wudi]

Summary

• Added support for x86 and x86_64 architectures in the Rust build system
• Updated nuttx_rust_target_triple function in cmake/nuttx_add_rust.cmake to handle x86 and x86_64 target triples
• Updated RUST_TARGET_TRIPLE macro in tools/Rust.mk to include x86 and x86_64 target triples

Impact

• Enables Rust crate compilation for x86 and x86_64 platforms
• No functional changes for existing architectures (ARM, RISC-V, etc.)
• Improves platform compatibility and expands Rust support in NuttX

Testing

GitHub CI and local build with rust on sim32/sim64

Refer to rust-lang/rust#136181

[nuttxpr]

[Experimental Bot, please feedback here]

Yes, this PR appears to meet the NuttX requirements, although some sections could be more detailed. Specifically:

• Summary: Good, clearly explains the what and how. Linking a related NuttX issue would strengthen it.
• Impact: While it mentions platform compatibility, it lacks specifics. Does this impact any existing drivers or configurations? The "No functional changes" statement needs clarification – no changes to what functionality? Explicitly stating "NO" for the other impact categories (build, hardware, documentation, security, backward/forward compatibility) would improve clarity.
• Testing: While referencing a Rust PR provides context, it doesn't fulfill the NuttX requirement of including actual testing logs. The mention of "GitHub CI and local build" is insufficient; provide snippets of successful build logs and ideally, some functional test output demonstrating that the Rust code operates as expected on the new architectures. Specify the OS and compiler used for the local build.

While the information provided points towards a compliant PR, adding the missing details (especially the testing logs and specific impact details) will ensure it fully adheres to the NuttX guidelines.