drm/amd/pm: fix workload mismatch on vega10

Workload number mapped to the correct one.
This issue is only on vega10.

Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>