issue/1194: add InfiniOps as submodule

[voltjia]

Summary

This PR adds InfiniOps as a git submodule under the root-level submodules/ directory:

submodules/InfiniOps

The submodule points to:

https://github.com/InfiniTensor/InfiniOps.git
branch: master
commit: 316ad6b0734b67a7c82362a86154a3301d0d6ea2

Changes

• Added .gitmodules entry for submodules/InfiniOps
• Added submodules/InfiniOps gitlink
• No source code, build script, or test file changes

Verification

Verified on nvidia that:

• .gitmodules contains the expected path, url, and branch
• git submodule status submodules/InfiniOps reports 316ad6b0734b67a7c82362a86154a3301d0d6ea2
• The staged diff only contains .gitmodules and submodules/InfiniOps gitlink