staging:iio:simple-dummy: 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>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/iio_simple_dummy_buffer.c

@@ -98,14 +98,6 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
 }
 
 static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {
-	/*
-	 * iio_sw_buffer_preenable:
-	 * Generic function for equal sized ring elements + 64 bit timestamp
-	 * Assumes that any combination of channels can be enabled.
-	 * Typically replaced to implement restrictions on what combinations
-	 * can be captured (hardware scan modes).
-	 */
-	.preenable = &iio_sw_buffer_preenable,
 	/*
 	 * iio_triggered_buffer_postenable:
 	 * Generic function that simply attaches the pollfunc to the trigger.