[Hardware][TPU][V1] Multi-LoRA implementation for the V1 TPU backend (#14238)

Signed-off-by: Akshat Tripathi <akshat@krai.ai>
Signed-off-by: Chengji Yao <chengjiyao@google.com>
Co-authored-by: Chengji Yao <chengjiyao@google.com>

vllm/config.py

@@ -2694,8 +2694,8 @@ class LoRAConfig:
     lora_extra_vocab_size: int = 256
     """Maximum size of extra vocabulary that can be present in a LoRA adapter
     (added to the base model vocabulary)."""
-    # This is a constant.
-    lora_vocab_padding_size: ClassVar[int] = 256
+    lora_vocab_padding_size: ClassVar[int] = current_platform\
+        .get_lora_vocab_padding_size()
     long_lora_scaling_factors: Optional[tuple[float, ...]] = None
     """Specify multiple scaling factors (which can be different from base model
     scaling factor - see eg. Long LoRA) to allow for multiple LoRA adapters
@@ -2723,6 +2723,7 @@ class LoRAConfig:
         factors.append(self.fully_sharded_loras)
         factors.append(self.lora_dtype)
         factors.append(self.lora_extra_vocab_size)
+        factors.append(self.lora_vocab_padding_size)
         factors.append(self.long_lora_scaling_factors)
         factors.append(self.bias_enabled)
         hash_str = hashlib.md5(str(factors).encode(),