tsl2561: remove executable permissions on files

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
tsl2561: fix indentation, style and namespace

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
tsl2561: change getLux calls to return an int

To follow with our simple API requirements, change the return value of getLux()
call to an int. This lets SWIG do a better job with generating an API

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>