iio: fix doc for iio_gts_find_sel_by_int_time

The kerneldoc for iio_gts_find_sel_by_int_time() has an error.
Documentation states that function is searching a selector for a HW-gain
while it is searching a selector for an integration time.

Fix the documentation by saying the function is looking for a selector
for an integration time.

Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
Signed-off-by: Matti Vaittinen <[e-mail]>
Link: https://lore.kernel.org/r/ZEIjI4YUzqPZk/9X@fedora
Signed-off-by: Jonathan Cameron <[e-mail]>

include/linux/iio/iio-gts-helper.h

···
 /**
  * iio_gts_find_sel_by_int_time - find selector matching integration time
  * @gts:	Gain time scale descriptor
- * @gain:	HW-gain for which matching selector is searched for
+ * @time:	Integration time for which matching selector is searched for
  *
  * Return:	a selector matching given integration time or -EINVAL if
  *		selector was not found.