drm/amd/display: add detile buffer size for renoir

Detile buffer size affects dcc caps, it was already added for
dcn2. Now add it for dcn21

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Roman Li <Roman.Li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>