platform/chrome: wilco_ec: Platform data shouldn't include kernel.h

Replace with appropriate types.h.

Also there is no need to include device.h, but mutex.h.
For the pointers to unknown structures use forward declarations.

In the *.c files we need to include all headers that provide APIs
being used in the module.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>