tca6416: add support for tca9539

Programming-wise tca6416 and tca9539 seem identical so all we have to
do is add the extra ofw_compat_data line.

Reviewed by: mw
Sponsored by: Traverse Technologies (providing Ten64 HW for testing)
Differential Revision: https://reviews.freebsd.org/D35702

(cherry picked from commit c4b98101c5b1dc34d077f078d04d777df3cf9e38)