iio: addac: stx104: Improve indentation in stx104_write_raw()

By bailing out early if chan->output is false for the IIO_CHAN_INFO_RAW,
indentation can be decreased by a tab and code readability improved.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/487d17da9e2612f3e6b2bd1c3def2fa1b955db9b.1680790580.git.william.gray@linaro.org


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>