xilinx: Add FDRSE_1, FDCPE_1.
xilinx: Add FDRSE_1, FDCPE_1.

antmicro/yosys,antmicro/yosys,cliffordwolf/yosys,antmicro/yosys,cliffordwolf/yosys,cliffordwolf/yosys,YosysHQ/yosys,cliffordwolf/yosys,antmicro/yosys,cliffordwolf/yosys,antmicro/yosys,antmicro/yosys,YosysHQ/yosys,YosysHQ/yosys,cliffordwolf/yosys,YosysHQ/yosys,YosysHQ/yosys,YosysHQ/yosys,cliffordwolf/yosys,cliffordwolf/yosys,cliffordwolf/yosys,antmicro/yosys,antmicro/yosys,YosysHQ/yosys,YosysHQ/yosys