add doc for patch_config (#574)

### What this PR does / why we need it?
add doc for patch_config
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
No code changed.

Signed-off-by: Shuqiao Li <celestialli@outlook.com>

Author: celestialli

vllm_ascend/patch/platform/patch_0_8_4/__init__.py

@@ -14,6 +14,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# What's Patched and how it works:
+# ** File: platform/patch_0_8_4/patch_config.py**
+#   1. `vllm.config.ModelConfig.__init__()`
+#    Why:
+#       It is hard coded for sleep mode to support cuda platform only
+#    How：
+#       Using a new method to check if sleep mode is available
+#    Related PR (if no, explain why): 1. refused by vllm. 2. vllm doesn't support 3. prepare to submit....
+#       https://github.com/vllm-project/vllm/pull/16562
+#    Future Plan:
+#       This patch is only used for 084 and can't be revert. just keep as it is.
 
 import vllm_ascend.patch.platform.patch_0_8_4.patch_config  # noqa
-import vllm_ascend.patch.platform.patch_0_8_4.patch_distributed  # noqa
+import vllm_ascend.patch.platform.patch_0_8_4.patch_distributed  # noqa