Revert "gpio: winbond: fix ISA_BUS_API dependency"

This reverts commit 92a8046c.

Now that the patch series changing ISA_BUS_API dependency to selection
was merged this reversion will do the same for gpio-winbond driver to
make it consistent with other ISA bus gpio drivers.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>