[Misc][V0 Deprecation] Remove multi-step worker (#1809)

### What this PR does / why we need it?
Remove multi-step worker

This PR is a part of
#1620.

- vLLM version: v0.9.2
- vLLM main:
vllm-project/vllm@235bfd5

---------

Signed-off-by: shen-shanshan <467638484@qq.com>

Author: shen-shanshan

vllm_ascend/patch/__init__.py

@@ -73,23 +73,6 @@
 #    Future Plan:
 #       Keep this patch in vllm-ascend.
 #
-# ** File: worker/patch_common/patch_multi_step_worker.py **
-# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-#   1. `vllm.spec_decode.multi_step_worker.MultiStepWorker.sampler_output`
-#    Why:
-#       There are cuda hard code (current_platform.is_cuda_alike()) in
-#       `MultiStepWorker.sampler_output`, and we need to use the patched `TP1DraftModelRunner` in it.
-#    How：
-#       Make speculative decoding extensible to different backends.
-#       - support attention metadata register to the set supported spec decode
-#       - offer a api in platform to determine whether spec decode is supported,
-#         and deprecate is_cuda_alike in it.
-#    Related PR (if no, explain why):
-#       - https://github.com/vllm-project/vllm/pull/15195
-#       - https://github.com/vllm-project/vllm-ascend/pull/395
-#    Future Plan:
-#       Revert it when the related pr is merged in vllm and vllm-ascend.
-#
 # ** File: worker/patch_common/patch_spec_decode_worker.py **
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 #   1. `vllm.spec_decode.spec_decode_worker.SpecDecodeWorker.create_worker`

vllm_ascend/patch/worker/patch_common/__init__.py

@@ -20,6 +20,5 @@
 import vllm_ascend.patch.worker.patch_common.patch_utils  # noqa isort:skip
 import vllm_ascend.patch.worker.patch_common.patch_distributed  # noqa
 import vllm_ascend.patch.worker.patch_common.patch_minicpm  # noqa
-import vllm_ascend.patch.worker.patch_common.patch_multi_step_worker  # noqa
 import vllm_ascend.patch.worker.patch_common.patch_sampler  # noqa
 import vllm_ascend.patch.worker.patch_common.patch_spec_decode_worker  # noqa