drm/amd/display: patch cases with unknown plane state to prevent warning

[Why]
DCN301 resource function is missing function pointer to
handle cases with unknown plane state.
This causes assertion when global state is validated while
using swizzle parameter as “DC_UNKNOWN”

[How]
Add function pointer to handle and patch cases when plane
state is unknown.

Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Swapnil Patel <Swapnil.Patel@amd.com>
Reviewed-by: Sung joon Kim <Sungjoon.Kim@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>