watchdog: iTCO_wdt: Add support for v3 silicon

Some new Atom's, eg Avoton and Bay Trail, have slightly different iTCO
functionality:
- The watchdog timer ticks at 1 second instead of .6 seconds

- Some 8 and 16-bit registers were combined into 32-bit registers

- Some registers were removed (DAT_IN, DAT_OUT, MESSAGE)

- The BOOT_STS field in TCO_STS was removed

- The NO_REBOOT bit is in the PMC area instead of GCS

Update the driver to support the above changes and bump the version to
1.11.

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>