iio:adc:ti-adc084s021: Tidy up white space around {}

Previously inconsistent with a space after { but not before }.
Tidy that up to avoid providing an example to copy into new drivers.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20211230174911.78291-14-jic23@kernel.org