09dc470982
It was annoying copy-paste happened across OpenCL device constructor, device enumeration and split kernel checks. Now those areas are using an utility function which returns pairs of platform and device IDs for devices which are supported by Cycles and enumeration is happening inside that list. This makes it so filtering is happening in a single place, so there's no need to keep 3 different functions in sync. This commit also fixes a bug with wrong enumeration of devices caused by recent fixes. Those fixes were in fact wrong and only happened to appear to be working on laptop with optimus card on Linux. Root of those issues is in fact in bad Linux driver for optimus cards.