drm/amd/pp: Refine the OD state checking code in smu7

drm/amd/pp: Refine the OD state checking code in smu7

if vddc restore to default value, driver clear the
bit of DPMTABLE_OD_UPDATE_VDDC and need to repopulate sclk
and mclk table.

1. Remove variable i checking code.
2. move clear DPMTABLE_OD_UPDATE_VDDC bit to the end of the
   function to avoid sclk table will not be updated.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>