[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>

csrc/dispatch_ffn_combine/op_kernel/utils/hccl_shmem.hpp

@@ -226,7 +226,7 @@ public:
         AscendC::CrossCoreSetFlag<0x0, PIPE_MTE3>(RECV_SYNC_EVENT_ID);
         AscendC::CrossCoreSetFlag<0x0, PIPE_MTE3>(SEND_SYNC_EVENT_ID);
         AscendC::CrossCoreWaitFlag(SEND_SYNC_EVENT_ID);
-        pipe_barrier(PIPE_ALL);
+        AscendC::PipeBarrier<PIPE_ALL>();
  
         ctrBuffer.SetValue(0, epStateValue_);
         AscendC::SetFlag<AscendC::HardEvent::S_MTE3>(EVENT_ID0);