ci/docker: bump risc-v toolchain gcc14

[shtirlic]

Summary

Revert to latest GCC14 due libcxx incompability with GCC15.
In #19030 risc-v toolchain was bumped to GCC15

We have old 17.0.6 LIBCXX with bunch of patches and it is incompatible with GCC15, stick for GCC14

Impact

Bring back failing risc-v builds with libcxx configs

[shtirlic]

@jerpelea sorry for noise

also can we have 2 risc-v toolchains in CI ?

[linguini1]

Which builds are failing?

[lupyuen]

FYI this is not a Full Revert. Based on #19030, the toolchain should be v14.2.0-3, not v14.3.0-1. We might have to revert back to v14.2.0-3 if we see more problems.

[lupyuen]

@linguini1 Below are the failed builds due to the Docker Image: https://nuttx-dashboard.org/d/fe2bqg6uk7nr4a/build-logs-from-nuttx-build-farm?from=now-2d&to=now&timezone=browser&var-arch=$__all&var-subarch=$__all&var-board=$__all&var-config=$__all&var-group=$__all&var-Filters=&orgId=1&refresh=15m

The Build Logs are at the NuttX Mirror Repo: https://github.com/NuttX/nuttx/actions/runs/26890338324

Update: Here's how it looks in the NuttX Build Monitor: https://lupyuen.github.io/nuttx-github-jobs/build-monitor

[shtirlic]

Which builds are failing?

All that depends on libcxx in configs