Bump riscv-gnu-toolchain from `eb1ee1b` to `6da3855`

Bumps [riscv-gnu-toolchain](https://github.com/riscv/riscv-gnu-toolchain) from `eb1ee1b` to `6da3855`.
- [Release notes](https://github.com/riscv/riscv-gnu-toolchain/releases)
- [Commits](https://github.com/riscv/riscv-gnu-toolchain/compare/eb1ee1b149612b74a390ed966525ce93d3efbac0...6da3855437e8ab7a8272400287186d5242610172

)

---
updated-dependencies:
- dependency-name: riscv-gnu-toolchain
  dependency-type: direct:production
...

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