gpio: pca935x: fix of-only probed devices

If the pca953x device is probed from OF using the proper OF probing then
the i2c-client will be NULL and the device probe will fail as id is NULL
and it isn't an ACPI device (previous drivers would simply OOPS out).

Add support for the of_device_id table having the same data as the others
so that the correct paths will be taken when registering a device.

An example of current valid of node which did not work:

	gpio@38 {
		compatible = "onsemi,pca9654", "nxp,pca9534";
		reg = <0x38>;
		interrupt-parent = <&gpio5>;
		interrupts = <25 IRQ_TYPE_LEVEL_LOW>;
	};

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>