RTS: Initialize DAC duotone multiplier values

Initialize the values used to multiply or divide the DAC duotone
in case there are no ADCs or DACs to handle them.

src/fe/map.c

@@ -105,6 +105,11 @@ mapPciModules( CDS_HARDWARE* pCds )
     dacdev = NULL;
     status = 0;
 
+    // initialize dac duotone multipliers/divisors in case
+    // we don't have one or the other of DAC or ADC cards
+    pCds->adcDuoToneDivisor[ 0 ] = 1;
+    pCds->dacDuoToneMultiplier[ 0 ] = 1;
+
    modCount = map_cards_2_slots ( &cdsPciModules ) ;
 
     // Map and Initialize ADC and DAC modules