drm/amd/display: Add new case to get spread spectrum info

[WHY]
New minor revision needs to be handled

[HOW]
Add switch case and assert to catch missing switch cases in the future
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Wayne Lin <waynelin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/bios/bios_parser2.c

@@ -836,8 +836,10 @@ static enum bp_result bios_parser_get_spread_spectrum_info(
 			return get_ss_info_v4_1(bp, signal, index, ss_info);
 		case 2:
 		case 3:
+		case 4:
 			return get_ss_info_v4_2(bp, signal, index, ss_info);
 		default:
+			ASSERT(0);
 			break;
 		}
 		break;