drivers/video: Fix an issue isx019 may freeze

isx019 driver freezes by I2C access in the interrupt context.
This I2C access is intended to stop data output from FPGA.
Delete this I2C access for the following reasons.
- Data output from FPGA does not affect power consumption
- There are no problems in capture restart without data output stop
  since restart is done by image data block first.

drivers/video/isx019.c

@@ -1671,14 +1671,6 @@ static int isx019_start_capture(FAR struct imgsensor_s *sensor,
 static int isx019_stop_capture(FAR struct imgsensor_s *sensor,
                                imgsensor_stream_type_t type)
 {
-  FAR isx019_dev_t *priv = (FAR isx019_dev_t *)sensor;
-  uint8_t regval;
-
-  regval = FPGA_DATA_OUTPUT_STOP;
-  nxmutex_lock(&priv->fpga_lock);
-  fpga_i2c_write(priv, FPGA_DATA_OUTPUT, &regval, 1);
-  fpga_activate_setting(priv);
-  nxmutex_unlock(&priv->fpga_lock);
   return OK;
 }