extcon: fsa9480: Support the FSA880 variant

The older compatible variant of this chip is called FSA880
and works the same way, if we need some quirks in the future,
it is good to let it have its own compatible string.

Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>