iio: dummy: iio_simple_dummy: Demote unworthy kerneldocs and correct wrong parameter in docs

File header comments are not good candidates for kerneldoc.  Neither
are generic comment blocks.

Fixes the following W=1 kernel build warning(s):

 drivers/iio/dummy/iio_simple_dummy.c:26: warning: cannot understand function prototype: 'const struct config_item_type iio_dummy_type = '
 drivers/iio/dummy/iio_simple_dummy.c:564: warning: Function parameter or member 'name' not described in 'iio_dummy_probe'
 drivers/iio/dummy/iio_simple_dummy.c:564: warning: Excess function parameter 'index' description in 'iio_dummy_probe'
 drivers/iio/dummy/iio_simple_dummy.c:700: warning: cannot understand function prototype: 'const struct iio_sw_device_ops iio_dummy_device_ops = '
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dummy/iio_simple_dummy.c

 // SPDX-License-Identifier: GPL-2.0-only
-/**
+/*
  * Copyright (c) 2011 Jonathan Cameron
  *
  * A reference industrial I/O driver to illustrate the functionality available.
@@ -553,7 +553,7 @@ static int iio_dummy_init_device(struct iio_dev *indio_dev)
 
 /**
  * iio_dummy_probe() - device instance probe
- * @index: an id number for this instance.
+ * @name: name of this instance.
  *
  * Arguments are bus type specific.
  * I2C: iio_dummy_probe(struct i2c_client *client,
@@ -689,7 +689,7 @@ static int iio_dummy_remove(struct iio_sw_device *swd)
 
 	return 0;
 }
-/**
+/*
  * module_iio_sw_device_driver() -  device driver registration
  *
  * Varies depending on bus type of the device. As there is no device