Fixed the INACCURATE bug for position control loop
Fixed the INACCURATE bug for position control loop

Symptom: the final PULSE_CMD to FPGA is not aligned with the pos_cmd given
         by motion controller.
Reason:
        The stepgen->cur_pos has to be calculated based on the integer
        pulse ticks sent to FPGA, otherwise the position loop control
        results would be incorrect.

araisrobo/linuxcnc,araisrobo/linuxcnc,araisrobo/linuxcnc,araisrobo/linuxcnc,araisrobo/linuxcnc