Vulkan convolution touchups. (#50329)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/50329
Test Plan: Imported from OSS
Reviewed By: SS-JIA
Differential Revision: D25869147
Pulled By: AshkanAliabadi
fbshipit-source-id: b8f393330b68912506fdaefaf62a455dc192e36c
