device property: Introduce fwnode_device_is_compatible() helper

The fwnode_device_is_compatible() helper searches for the
given string in the "compatible" string array property and,
if found, returns true.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>