Enable building RocksDB on non-Linux aarch64 OSes

[brad0]

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Now that RocksDB has been synced up to 6.29, which includes the changes mentioned in the CMake comment, support for building on non-Linux aarch64 OSes can be enabled.

Description

RocksDB on aarch64 is currently disabled for build on non-Linux OSes

Release Notes

Enabled building RocksDB on aarch64 for non-Linux OSes

How can this PR be tested?

Build on non-Linux OS like macOS, FreeBSD, OpenBSD, etc. and verify RocksDB is built.

Basing the PR against the correct MariaDB version

• [ ] This is a new feature or a refactoring, and the PR is based against the main branch.
• [x] This is a bug fix, and the PR is based against the earliest maintained branch in which the bug can be reproduced.

PR quality check

• [x] I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• [x] For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.