drm/amd/powerplay: added grbm_idx_mutex lock/unlock to cgs v2

  - v2: rename param 'en' as 'lock'

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2 files changed