dm: gpio: pca953x: introduce driver model support for pca953x

dm: gpio: pca953x: introduce driver model support for pca953x

Introduce a new driver that supports driver model for pca953x.
The pca953x chips are used as I2C I/O expanders.
This driver is designed to support the following chips:
"
4 bits: pca9536, pca9537
8 bits: max7310, max7315, pca6107, pca9534, pca9538, pca9554,
        pca9556, pca9557, pca9574, tca6408, xra1202
16 bits: max7312, max7313, pca9535, pca9539, pca9555, pca9575,
         tca6416
24 bits: tca6424
40 bits: pca9505, pca9698
"
But for now this driver only supports max 24 bits and pca953x compatible
chips. pca957x compatible chips are not supported now.
These can be addressed when we need to add such support for the different
chips.
This driver has been tested on i.MX6 SoloX Sabreauto board with max7310
i2c expander using gpio command as following:

=>gpio status -a
Bank gpio@30_:
gpio@30_0: input: 1 [ ]

=> dm tree:
 i2c         [   ]    |   |   `-- i2c@021a8000
 gpio        [   ]    |   |       |-- gpio@30
 gpio        [   ]    |   |       `-- gpio@32

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Wenyou Yang <wenyou.yang@atmel.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Purna Chandra Mandal <purna.mandal@microchip.com>
Cc: Thomas Chou <thomas@wytron.com.tw>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Andrea Scian <andrea.scian@dave.eu>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Michal Simek <michal.simek@xilinx.com> #on ZynqMP zcu102