drm/amd/pm: add get_gpu_metrics support for 15.0.8

drm/amd/pm: add get_gpu_metrics support for 15.0.8

export .get_gpu_metrics interface for 15.0.8

v2: Remove members already exposed by other interfaces, use mask,
logical conversion (Lijo)

v3: Use correct logic for hbm stacks loop (Lijo)
Remove buffer allocation

v4: Make out of bound check outside loop (Lijo)

v5: fix locking in error case (Alex)

Signed-off-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>