gfx1201 (RDNA4, R9700) build fails: __builtin_amdgcn_wmma_f32_16x16x16_f16_w32 not supported

Environment:
- GPU: AMD Radeon AI PRO R9700 (gfx1201, RDNA4)
- ROCm: 7.2.2 (AMD clang 22.0.0git roc-7.2.2)
- rocWMMA headers: installed with gfx12 support (config.hpp has gfx1200/gfx1201)

Error:
fatal error: error in backend: Cannot select: intrinsic %llvm.amdgcn.wmma.f32.16x16x16.f16
(compiling ds4_rocm.cu with --offload-arch=gfx1201)

Root cause:
rocm/ds4_rocm_q8.cuh uses __builtin_amdgcn_wmma_f32_16x16x16_f16_w32 without
any arch guard. This builtin works on gfx1151 (RDNA3.5) but gfx1201 (RDNA4)
uses WMMA v2 intrinsics with a different API.

Workaround: using the May 19 binary (pre-WMMA, pre-SSD-streaming), which works
fine since the 121 GB RAM system doesn't need SSD streaming for the 72.8 GB model.