[v5.0.x] fix: Set accelerator rcache flag in btl/ofi for accelerator memory

[a-szegel]

(cherry picked from commit 19a5405)

[Copilot]

Pull Request Overview

This PR fixes an issue in the Open MPI BTL/OFI module where accelerator memory registration was not properly flagged. The change ensures that when registering memory through the BTL/OFI interface, accelerator memory (such as GPU memory) is correctly identified and marked with the appropriate cache flags.

• Adds accelerator memory detection during memory registration in BTL/OFI module
• Sets the MCA_RCACHE_FLAGS_ACCELERATOR_MEM flag when accelerator memory is detected

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[jsquyres]

Pull Request Overview

This PR fixes an issue in the Open MPI BTL/OFI module where accelerator memory registration was not properly flagged. The change ensures that when registering memory through the BTL/OFI interface, accelerator memory (such as GPU memory) is correctly identified and marked with the appropriate cache flags.

Sorry -- I just wanted to try adding a copilot code review to see what would happen. This PR was my random guinea pig. 😄