Input: docs - use PROPERTY_ENTRY_U32() directly

Instead of using PROPERTY_ENTRY_INTEGER() with explicitly supplied type,
use PROPERTY_ENTRY_U32() dedicated macro.

It will help modify internals of built-in device properties API.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>