evas 3d: Fix shaders compilation (parallax and normal)

evas 3d: Fix shaders compilation (parallax and normal)

My nvidia EGL driver coultn't compile some shaders because of
the error:
  error C1059: non constant expression in initialization

The proposed patch at D4068 is not acceptable since it just
brings the original problem back. Instead, make sure all vec3
variables are initialized in main() or another function, not in
the global scope.

I tested all examples in evas