i965: Stop using BRW_RASTRULE_LOWER_RIGHT on Gen4-5.

i965: Stop using BRW_RASTRULE_LOWER_RIGHT on Gen4-5.

This effectively reverts Robert Ellison's 2009 commit
cc8afbd3862fedfe42e51c3774960d1c7078ec53.

I'm not seeing any GL spec text indicating that UPPER won't work.
On Gen6+, this bit moved to 3DSTATE_WM as a single bit, controlling
UPPER_LEFT vs. UPPER_RIGHT.  There is no way to request LOWER_RIGHT,
so UPPER_RIGHT is the best you can do.

In the G45 docs, it's marked as "Reserved" as well, but we just
decided to use it anyway.

This patch unifies the behavior between Gen4-5 and Gen6+.

Note that this is separate from point sprite texcoord behavior.

Reviewed-by: Rafael Antognolli <rafael.antognolli@intel.com>