iio:gp2ap020a00f: Remove redundant call to iio_sw_buffer_preenable()

The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/gp2ap020a00f.c

@@ -1483,7 +1483,6 @@ static int gp2ap020a00f_buffer_predisable(struct iio_dev *indio_dev)
 }
 
 static const struct iio_buffer_setup_ops gp2ap020a00f_buffer_setup_ops = {
-	.preenable = &iio_sw_buffer_preenable,
 	.postenable = &gp2ap020a00f_buffer_postenable,
 	.predisable = &gp2ap020a00f_buffer_predisable,
 };