media: v4l2-fwnode: Switch to use fwnode_property_count_uXX()

Use fwnode_property_count_uXX() directly, that makes code neater.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>