Fix a segfault in dffinit when the value has too few bits
Fix a segfault in dffinit when the value has too few bits

The code was already trying to add the required number of bits, but
fell one short of the mark.

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