mfd: lpc_ich: Only configure watchdog or GPIO when present

Some chipsets don't currently have GPIO support enabled.  For these
chipsets don't go through the process of initializing the GPIO region.

Make the same change for the watchdog initialization for chipsets which
may not enable the WDT in the future.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Rajat Jain <rajatjain@juniper.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>