drm/amd/display: Add missing mask for DCN3

[Why]
DCN3 is not reusing DCN1 mask_sh_list, causing
SURFACE_FLIP_INT_MASK missing in the mapping.

[How]
Add the corresponding entry to DCN3 list.

Signed-off-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>