vulkan: combine duplicated fastdiv functions, rename the one optimizing small divs (#27526)

* vulkan: combine duplicated fastdiv functions, rename the one optimizing small divs

* remove one more fastdiv

ggml/src/ggml-vulkan/vulkan-shaders/conv2d_mm.comp

@@ -19,6 +19,7 @@
 #endif
 
 #include "types.glsl"
+#include "utils.glsl"
 
 // shape notation: [dim(N), ..., dim(0)] -- stride(dim(j)) >= stride(dim(i)) if i > j
 layout(binding = 0) readonly buffer A {
@@ -193,14 +194,6 @@ uint32_t       Br    = tid / BS_NPQ;
 uint32_t       Bc    = tid % BS_NPQ;
 const uint32_t BrpWg = WG_SIZE / BS_NPQ;
 
-// see init_fastdiv_values in ggml-vulkan.cpp
-uint fastdiv(uint n, uint mp, uint L) {
-    uint msbs, lsbs;
-    // msbs = mulhi(n, mp)
-    umulExtended(n, mp, msbs, lsbs);
-    return (msbs + n) >> L;
-}
-
 #ifdef COOPMAT2
 #define ACC_TYPE float16_t