Add process and thread names and pids and a function to extract
this info from relevant amdgpu_vm.

v2: Add documentation and fix identation.

v3: Add getter and setter functions for amdgpu_task_info.
Signed-off-by: NAndrey Grodzovsky <andrey.grodzovsky@amd.com>
Acked-by: NJim Qu <Jim.Qu@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>