i965/eu: Consider QtrCtrl 3Q-4Q in typed surface message descriptor setup.

i965/eu: Consider QtrCtrl 3Q-4Q in typed surface message descriptor setup.

In SIMD32 programs the compiler is responsible for providing the
appropriate half of the sample mask in the message header, so the
first and third quarters both map to the first slot group of the
provided 16-bit half, while the second and fourth quarters map to the
second slot group -- IOW they should be equivalent to 1Q and 2Q modulo
two.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>