More $eq/$ne/$eqx/$nex fixes in opt_const
More $eq/$ne/$eqx/$nex fixes in opt_const

azonenberg/yosys,cliffordwolf/yosys,swallat/yosys,antmicro/yosys,swallat/yosys,cliffordwolf/yosys,SymbiFlow/yosys,azonenberg/yosys,SymbiFlow/yosys,YosysHQ/yosys,SymbiFlow/yosys,SymbiFlow/yosys,antmicro/yosys,YosysHQ/yosys,SymbiFlow/yosys,cliffordwolf/yosys,swallat/yosys,azonenberg/yosys,YosysHQ/yosys,azonenberg/yosys,YosysHQ/yosys,cliffordwolf/yosys,swallat/yosys,azonenberg/yosys,azonenberg/yosys,cliffordwolf/yosys,cliffordwolf/yosys,azonenberg/yosys,swallat/yosys,antmicro/yosys,YosysHQ/yosys,swallat/yosys,antmicro/yosys,antmicro/yosys,swallat/yosys,YosysHQ/yosys,swallat/yosys,cliffordwolf/yosys,azonenberg/yosys,cliffordwolf/yosys,cliffordwolf/yosys,antmicro/yosys,YosysHQ/yosys,swallat/yosys,YosysHQ/yosys,azonenberg/yosys,SymbiFlow/yosys,antmicro/yosys,antmicro/yosys,SymbiFlow/yosys,SymbiFlow/yosys