staging: iio: light: Checkpatch fixes tsl2x7x_core.c

This patch fixes these errors and warning messages found by
checkpatch.pl:
ERROR: return is not a function, parentheses are not required.
WARNING: space prohibited before semicolon.

Signed-off-by: Aybuke Ozdemir <aybuke.147@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>