[2/N][Pangu][MoE] Remove Pangu Related Code (#5130)

### What this PR does / why we need it?
Remove Pangu Related Code

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
e2e & ut

- vLLM version: v0.12.0
- vLLM main:
ad32e3e19c

---------

Signed-off-by: weichen <calvin_zhu0210@outlook.com>

vllm_ascend/quantization/quant_config.py

@@ -134,9 +134,6 @@ class AscendQuantConfig(QuantizationConfig):
             'fa_quant_type' in self.quant_description.keys() and \
             self.quant_description['fa_quant_type'] is not None:
             return AscendKVCacheMethod(self, prefix)
-        elif isinstance(layer, Attention) and self.quant_description.get(
-                'kv_quant_type') == 'C8':
-            return AscendKVCacheMethod(self, prefix)
         elif isinstance(layer, FusedMoE):
             if self.is_layer_skipped_ascend(prefix,
                                             self.packed_modules_mapping):