Reduce foot print of cycle1 -> cycle2 dma size change for fast adcs.

Old code for changing DMA size from the ( possibly smaller ) first cycle was too expensive in some sense, causing momentary channel hopping on the ADC when run at 65k and time_shift=0.

The new code just changes the size value of an already existing DMA module instead of totally recreating it.

src/include/drv/iop_adc_functions.c

@@ -443,7 +443,7 @@ iop_adc_read( adcInfo_t* adcinfo, int cpuClk[] )
             *packedData = DUMMY_ADC_VAL;
             if ( first_adc_read )
             {
-                plx9056_adc_dma_setup(card,
+                plx9056_adc_dma_set_size(card,
                           cdsPciModules.adcChannels[ card ] * UNDERSAMPLE * 4 );
             }
             plx9056_adc_dma_start( card );