SOLVED!!! Mystery of PINs 0-20 configurations.

Just add this to the GPIOinit() function :

apiRetStatus = CyU3PDeviceGpioOverride(18, CyTrue);
apiRetStatus = CyU3PGpioSetSimpleConfig(18, &gpioConfig);

Make sure you DONOT add anything in the main matrix mapping for the GPIOs else the USB fails to re-enumerate!

 io_cfg.gpioSimpleEn[0]  = 0x00000000; << KEEP THIS ZERO io_cfg.gpioSimpleEn[1]  = DAC_PORTS | 0x00002000 ;
 io_cfg.gpioComplexEn[0] = 0;
 io_cfg.gpioComplexEn[1] = 0;