Blender Git Loki

EEVEE: Micro optimize disk light

Try to never do operation twice and try to use MADD operations. Even if this
is very unlikely to make any difference, it can help compilers do some
optimization. I did not measure any difference as probes have much higher
impact on render time because of texture lookups.

Note that disk light is currently the most expensive light type so it
does not hurt to micro optimize.