HIP: implement FlashAttention via rocWMMA for CDNA and RDNA3+ (#12032)

Adds GGML_HIP_ROCWMMA_FATTN and rocwmma header check
Adds rocWMMA support to fattn-wmma-f16

---

Signed-off-by: Carl Klemm <carl@uvos.xyz>
Co-authored-by: Johannes Gäßler <johannesg@5d6.de>
Co-authored-by: Ben Jackson <ben@ben.com>

ggml/src/ggml-hip/CMakeLists.txt

@@ -39,6 +39,12 @@ endif()
 find_package(hip     REQUIRED)
 find_package(hipblas REQUIRED)
 find_package(rocblas REQUIRED)
+if (GGML_HIP_ROCWMMA_FATTN)
+    CHECK_INCLUDE_FILE_CXX("rocwmma/rocwmma.hpp" FOUND_ROCWMMA)
+    if (NOT ${FOUND_ROCWMMA})
+        message(FATAL_ERROR "rocwmma has not been found")
+    endif()
+endif()
 
 if (${hip_VERSION} VERSION_LESS 5.5)
     message(FATAL_ERROR "At least ROCM/HIP V5.5 is required")
@@ -107,6 +113,10 @@ if (GGML_HIP_NO_VMM)
     add_compile_definitions(GGML_HIP_NO_VMM)
 endif()
 
+if (GGML_HIP_ROCWMMA_FATTN)
+    add_compile_definitions(GGML_HIP_ROCWMMA_FATTN)
+endif()
+
 if (NOT GGML_CUDA_FA)
     add_compile_definitions(GGML_CUDA_NO_FA)
 endif()