Staging: iio: Alignment should match open parenthesis

This patch arranges multiple-line parameters in accordance with
the parameter above them to improve coding style.
Found by checkpatch.pl

Signed-off-by: Cristina Opriceana <cristina.opriceana@gmail.com>
Reviewed-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>