[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/attention/attention_v1.py

@@ -79,15 +79,6 @@ class AscendAttentionBackend(AttentionBackend):
     ) -> Tuple[int, ...]:
         return (2, num_blocks, block_size, num_kv_heads, head_size)
 
-    @staticmethod
-    def get_bsh_kv_cache_shape(
-        num_blocks: int,
-        block_size: int,
-        num_kv_heads: int,
-        head_size: int,
-    ) -> Tuple[int, ...]:
-        return (2, num_blocks, block_size, num_kv_heads * head_size)
-
     @staticmethod
     def swap_blocks(
         src_kv_cache: List[torch.Tensor],