[AMDGPU][printf] Run AMDGPUPrintfRuntimeBindingPass in -O0

AMDGPUPrintfRuntimeBindingPass is not run in the IR optimization
pipeline with -O0.

This means that with OpenCL the printf definition coming from
device_libs gets linked with the user's code, which blocks
AMDGPUPrintfRuntimeBindingPass from working after the linkage is done.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D146720