[AMDGPU] Rename "LDS lowering" pass name.

Rename the name of "LDS lowering" pass from `amdgpu-disable-lower-module-lds` to
`amdgpu-enable-lower-module-lds` as later is consistent and reads better.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D100441