drm/amd/display: Fix cleanup typo in MPCC visual confirm

[Why]
Typo in MPCC visual confirmation.

[How]
Fix to correct values.

Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>