anv/gen11+: Disable object level preemption
An unknown issue is causing vs push constants to become corrupted during object-level preemption. For now, restrict to command buffer level preemption to avoid rendering corruption. Cc: <mesa-stable@lists.freedesktop.org> Reviewed-by:Jason Ekstrand <jason@jlekstrand.net> Part-of: <!5110> (cherry picked from commit 81201e46)