CUDA: experimental native mxfp4 support for blackwell (#17906)

* CUDA: experimental native mxfp4 support for blackwell

* optimize load_tiles

* optimize quantize_mxfp4

* cleanup

* first pass review: formatting

* use interleaved layout for mma

* mmq: add assert for size

* use __nv_fp4x4_e2m1

* use iter_k as 512, cleanup

* Use 1200 as blackwell instead of 1000

* address review comments

* mmq: fix stride

* quantize.cu: use reference impl of e8m0 scale

* address review comments

* add 120f-virtual + minor fixes

---------

Co-authored-by: Aman Gupta <aman>

ggml/src/ggml-cuda/quantize.cuh

@@ -25,3 +25,17 @@ void quantize_mmq_q8_1_cuda(
         const float * x, const int32_t * ids, void * vy,
         ggml_type type_src0, int64_t ne00, int64_t s01, int64_t s02, int64_t s03,
         int64_t ne0, int64_t ne1, int64_t ne2, int64_t ne3, cudaStream_t stream);
+
+void quantize_mmq_mxfp4_cuda(const float *   x,
+                             const int32_t * ids,
+                             void *          vy,
+                             ggml_type       type_src0,
+                             int64_t         ne00,
+                             int64_t         s01,
+                             int64_t         s02,
+                             int64_t         s03,
+                             int64_t         ne0,
+                             int64_t         ne1,
+                             int64_t         ne2,
+                             int64_t         ne3,
+                             cudaStream_t    stream);