This PR addresses several portability and technical debt issues in the mnemofs filesystem by resolving source-level TODO items.
Changes:
- Implemented a portable fallback for mfs\_clz (Count Leading Zeros) in fs/mnemofs/mnemofs.h using a binary search approach. This ensures compatibility with non-GCC compilers.
- Removed the redundant 8-bit mfs\_arrhash and consolidated hashing with the existing 16-bit mfs\_hash in mnemofs\_util.c.
- Removed the related TODO comments in mnemofs.h and mnemofs\_util.c.
- Fixed NuttX style (indentation and braces) in the fallback bit primitives.
Signed-off-by: Sumit <sumit6307@gmail.com>