[Build] Add support for Ascend950 chip (#7151)

### What this PR does / why we need it?
This PR adds support for the Ascend950 chip. This includes:
- Updating build scripts (`CMakeLists.txt` and `setup.py`) to recognize
the Ascend950 chip and set appropriate compilation flags.
- Disabling a set of custom operators that are not yet supported on the
Ascend950 hardware target.
- Performing a codebase-wide refactoring of `pipe_barrier()` calls to
the namespaced `AscendC::PipeBarrier<>()` for improved code consistency
and adherence to the latest API standards.

Ascend950DT e2e passed (Qwen3-32B-MXFP8) and CI passed
- vLLM version: v0.16.0
- vLLM main:
4034c3d32e
---------
Signed-off-by: linfeng-yuan <1102311262@qq.com>

CMakeLists.txt

@@ -61,7 +61,7 @@ set(VLLM_ASCEND_CUSTOM_OP
     ${CMAKE_CURRENT_SOURCE_DIR}/csrc/batch_matmul_transpose/op_kernel/batch_matmul_transpose_kernel.cpp
 )
 
-set(VLLM_ASCEND_CUSTOM_OP_EXCLUDE
+set(VLLM_ASCEND_CUSTOM_OP_EXCLUDE_310P
     ${CMAKE_CURRENT_SOURCE_DIR}/csrc/kernels/bgmv_expand.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/csrc/kernels/bgmv_shrink.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/csrc/kernels/sgmv_expand.cpp
@@ -70,10 +70,21 @@ set(VLLM_ASCEND_CUSTOM_OP_EXCLUDE
     ${CMAKE_CURRENT_SOURCE_DIR}/csrc/batch_matmul_transpose/op_kernel/batch_matmul_transpose_kernel.cpp
 )
 
+set(VLLM_ASCEND_CUSTOM_OP_EXCLUDE_ASCEND950
+    ${CMAKE_CURRENT_SOURCE_DIR}/csrc/mla_preprocess/op_kernel/mla_preprocess_kernel.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/csrc/batch_matmul_transpose/op_kernel/batch_matmul_transpose_kernel.cpp
+)
+
 if(SOC_VERSION MATCHES "ascend310p.*")
     message(STATUS "310P hardware detected: disabling MLAPO operators")
     message(STATUS "310P hardware detected: excluding batch_matmul_transpose operators")
-    list(REMOVE_ITEM VLLM_ASCEND_CUSTOM_OP ${VLLM_ASCEND_CUSTOM_OP_EXCLUDE})
+    list(REMOVE_ITEM VLLM_ASCEND_CUSTOM_OP ${VLLM_ASCEND_CUSTOM_OP_EXCLUDE_310P})
+endif()
+
+if(SOC_VERSION MATCHES "ascend950")
+    message(STATUS "A5 hardware detected: disabling MLAPO operators")
+    message(STATUS "A5 hardware detected: excluding batch_matmul_transpose operators")
+    list(REMOVE_ITEM VLLM_ASCEND_CUSTOM_OP ${VLLM_ASCEND_CUSTOM_OP_EXCLUDE_ASCEND950})
 endif()
 
 ascendc_library(vllm_ascend_kernels SHARED