Revert "intel/compiler: make uses_pos_offset a tri-state"

This reverts commit 5489033f.

The problem I was trying to address is that we were programming the 3DSTATE_PS::PositionXYOffsetSelect bit differently with GPL (CENTROID) than without (NONE).

I failed to understand that this bit also impacts the thread payload layout. GPL fragment shaders don't know ahead of time if pos_offset is going to be used. It'll be choosen at runtime base on push constant bits. So we need to program this bit different just to have a payload matching the compiled shader code.

This fixes the freedoom replay with GPL FS shader in SIMD32.

Signed-off-by: Lionel Landwerlin lionel.g.landwerlin@intel.com