Building metal kernels emits noisy warning / note, 126 times at present. #4670

Since #3161 (1-bit affine quantization) I think, building the Metal kernels (from source) emits the same warning once per qmv_fast_impl instantiation, 126 in total:

mlx/backend/metal/kernels/quantized.h:933:67: warning: comparison of integers of different signs: 'unsigned int' and 'const constant int' [-Wsign-compare]
    bool in_bounds = (aligned_end + simd_lid * values_per_thread) < in_vec_size;

simd_lid is uint, so the left side is promoted to unsigned. All values are non-negative here, so the result is correct; it's just noise in a -Wall -Wextra build that hides real warnings.

Possible one-line fix:

bool in_bounds =
    (aligned_end + static_cast<int>(simd_lid) * values_per_thread) < in_vec_size;

Environment: macOS 27, Xcode 27, M5 Max, building from main.