Staging: IIO: Add tsl2560-2 support to tsl2563 driver.

Minimal changes to driver. Just adds the device to the id
table and adjusts the Kconfig elements appropriately.

Adding further similar chips from TAOS is complicated by their
different conversion functions (and hence left for now).

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Amit Kucheria <amit.kucheria@verdurent.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>