media: v4l2-fwnode: simplify v4l2_fwnode_reference_parse_int_props() call

The v4l2_fwnode_reference_parse_int_props() has a big name, causing
it to cause coding style warnings. Also, it depends on a const
struct embedded indide a function.

Rearrange the logic in order to move the struct declaration out
of such function and use it inside this function.

That cleans up some coding style issues.

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