Marvell/Drivers: MvPca95xxDxe: Introduce GPIO expander driver

Marvell Armada 7k/8k-based platforms may use Pca95xx to extend
amount of the GPIO pins.

This patch introduces support for them. The new driver implements
a generic EMBEDDED_GPIO protocol.

In order to ease description of used PCA9XXX controllers
add a common enum type. It can be used e.g. in the board description
library to specify the expander model on a board (instead of passing
a raw number). Update relevant libraries.

Driver is based on initial work done by Allen Yan <yanwei@marvell.com>.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>