device property: Add headers to the Driver Core entry in MAINTAINERS

The header files (fwnode.h and property.h) are part of the device
property API, which in its turn is part of driver core. Add the
missed headers to the corresponding record in the MAINTAINERS database.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230327130150.84114-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>