gpio: pca953x: add support for pca9505

Now that pca953x driver can handle GPIO expanders with more than 32
bits this patch adds the support for the pca9505 which cam with 40
GPIOs.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>