The purpose of this patch is to Implement registration of callback functions in the amdgpu plugin by looking up corresponding callbacks in libomptarget. The overall design document is https://rice.app.box.com/s/pf3gix2hs4d4o1aatwir1set05xmjljc
Defined an object of type OmptDeviceCallbacksTy in the amdgpu plugin for holding the tool-provided callback functions. Implemented a global constructor in the plugin that creates a connector object to connect with libomptarget. The callbacks that are already registered with libomptarget are looked up and registered with the plugin.
Depends on D123974
Patch from John Mellor-Crummey <email@example.com>
(With contributions from Dhruva Chakrabarti <Dhruva.Chakrabarti@amd.com>)