[Pytorch][vulkan] Simplify depthwise conv to remove bounds compute (#89950)
Right now we are doing bounds check and reduce compute according to bounds
check. However this can lead to thread divergence.
Furthermore since textures provide handling of border region, it should be safe
to use negative indexing.
Differential Revision: [D41006645](https://our.internmc.facebook.com/intern/diff/D41006645/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89950
Approved by: https://github.com/salilsdesai
