gpio: pca953x: add pcal6416 to the of_device_id table

When adding support for the pcal6416, the of_device_id table was left out,
add the proper entry.

Fixes: aac1e3c9 ("gpio: pca953x: add support for pcal6416 type")
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>