Upgrade rocm-flashinfer to latest upstream trunk.

[diptorupd]

The present amd-integration branch is a fork of an older version of flashinfer-ai/flashinfer (v0.2.5.1). We should plan to update the version to the latest trunk.

There are few design decisions that need to be sorted out prior to the upgrade:

1. rocm-flashinfer made changes to the directory layout of the project.
   a. ./csrc -> ./flashinfer/csrc
   b. ./include -> ./libflashinfer/include
2. We still use the removed aot-build-utils for AOT builds
3. We use an old torch compile for JIT compilation.

There might be other issues that we need to discuss and resolve before we decide upon an upgrade strategy. The issue serves as a medium to discuss and decide the best way forward.

[diptorupd]

Marking as closed since upstream trunk is a moving target. We will keep updating amd-flashinfer to specific upstream releases based on user requests. The current goal is to update to v0.5.3 and is being done in #173.