mfd: watchdog: iTCO_wdt: Expose watchdog properties using platform data

mfd: watchdog: iTCO_wdt: Expose watchdog properties using platform data

Intel Sunrisepoint (Skylake PCH) has the iTCO watchdog accessible across
the SMBus, unlike previous generations of PCH/ICH where it was on the
LPC bus. Because it's on the SMBus, it doesn't make sense to pass around
a 'struct lpc_ich_info', and leaking the type of bus into the iTCO
watchdog driver is kind of backwards anyway.

This change introduces a new 'struct itco_wdt_platform_data' for use
inside the iTCO watchdog driver and by the upcoming Intel Sunrisepoint
code, which neatly avoids having to include lpc_ich headers in the i801
i2c driver.

This change is overdue because lpc_ich_info has already found its way
into other TCO watchdog users, notably the intel_pmc_ipc driver where
the watchdog actually isn't on the LPC bus as far as I can see.

A simple translation layer is provided for converting from the existing
'struct lpc_ich_info' inside the lpc_ich mfd driver.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Acked-by: Darren Hart <dvhart@linux.intel.com> [drivers/x86 refactoring]
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>