[Misc] Add cann custom ops to .gitignore (#4670)

### What this PR does / why we need it?
Add `CANN-custom_ops--linux.aarch64.run` (generated during installing
vllm-ascend) to `.gitignore`.

- vLLM version: 86e178f7c4d8c3b0eaf3c8e3f810a83f63b90e24
- vLLM main:
vllm-project/vllm@86e178f

Signed-off-by: Shanshan Shen <[email protected]>

Author: shen-shanshan

.gitignore

@@ -209,3 +209,4 @@ kernel_meta/
 
 # generated by CANN
 fusion_result.json
+csrc/output/