Fix [Not supported] status for get_compute_process_info_by_pid

On some systems [rocm-smi --showpids] reports
get_compute_process_info_by_pid, Not supported on the given system
[PID] [PROCESS NAME] 1 UNKNOWN UNKNOWN UNKNOWN

get_compute_process_info_by_pid fails because cu_occupancy debugfs method
is not provided on some graphics cards and GFX revisions by design

Proposing a change to return success status when only cu_occupancy debugfs method
is not found and provide cu_occupancy invalidation value to mark only
this parameter as UNKNOWN

Change-Id: Iae37070d9bd19483b4e6c8ee24c7d9a4c92f00d7
Signed-off-by: Vladimir Stempen <Vladimir.Stempen@amd.com>
Reviewed-by: Galantsev, Dmitrii <dmitrii.galantsev@amd.com>

include/rocm_smi/rocm_smi.h

@@ -1134,6 +1134,8 @@ typedef struct {
     uint32_t cu_occupancy;    //!< Compute Unit usage in percent
 } rsmi_process_info_t;
 
+//! CU occupancy invalidation value for the GFX revisions not providing cu_occupancy debugfs method 
+#define CU_OCCUPANCY_INVALID 0xFFFFFFFF
 
 /**
  * @brief Opaque handle to function-support object