interchange: fix dedicated interconnect exploration
interchange: fix dedicated interconnect exploration

Signed-off-by: Alessandro Comodi <622632e70fd6771cf2cd943f69e5e51ab66adef8@antmicro.com>

YosysHQ/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr,SymbiFlow/nextpnr,YosysHQ/nextpnr,SymbiFlow/nextpnr