Instead of just calling it as "size", let's name it as "ioc_size",
as it reflects better its contents.

As this is constant along the function, also mark it as const.
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>