st/nine: Explicit nine requirements

st/nine: Explicit nine requirements

This patch raises nine requirements and disables nine for old
hw that don't match them.

Currently for these cards only games that don't have tight requirements
would work well with nine. However nine is missing several checks
regarding these limitations.
To make code and future patches less heavy, dropping support for these old
card seems a good solution.

That makes r500 the only dx9 generation cards supported by nine. It seems the one
with the less limitations for nine. Still not everything is ok, and we'll have
for example to implement shader recompilation for these cards to include
integer and boolean constants in the shader.
Eventually when this is done, we can reintroduce support for older cards.

Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Axel Davy <axel.davy@ens.fr>