toolchain: fix ARM R-profile multilib configuration

[lukileczo]

Description

Default GCC configuration chooses basic armv7 multilib for both ARM A- and R-profile. However ARM-R does not have MMU and GCC-provided libs for this target must be compiled with appropriate PIC flags.

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: armv8r52-mps3an536-qemu

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[github-actions]

Unit Test Results

7 700 tests  ±0   6 985 ✅ ±0   39m 15s ⏱️ + 1m 47s
  436 suites ±0     715 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 191cb9e. ± Comparison against base commit 97fb495.

[nalajcie]

Changes look sane, didn't test them but will give optimistic +1.

@badochov have a look at the proposed changes and verify if they are solved in newer GCC version when porting ;).

[badochov]

@lukileczo can you create a build docker image(only amd64 version is needed), and run test campaign on it to make sure other targets weren't affected by accident? To run test campaing you'll need to alter image in .github workflow and create PR on project, I did the same for my toolchain changes: https://github.com/phoenix-rtos/phoenix-rtos-project/pull/1161/files#diff-23b926d45f915c8730caad964c38d44468fa5930dc49c370939a8933535f8e77/

[lukileczo]

@badochov Everything seems to be working correctly - https://github.com/phoenix-rtos/phoenix-rtos-project/actions/runs/10828825270?pr=1162 (apart from the standard ia32 exit fail), also checked armv8r52-mps3an536-qemu build which went fine.

[badochov]

LGTM