staging: iio: tsl2583: fix multiline comment syntax

The definition of the tsl2583_device_lux struct has a series of single
line comments. There are two other cases where the multiline comments
did not have an initial blank line. Change these comments to use the
proper multiline syntax.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>