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

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

This reverts commit 5489033fa8568ecacafe32ceab36f89f2e14f3dc.

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>
Acked-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22938>