st/nine: Declare constants only up to the maximum needed.

st/nine: Declare constants only up to the maximum needed.

Previously 276 constants were declared everytime.

This patch makes shaders declare constants up to the maximum
constant needed and moves the moment we print the TGSI
shader after the moment we declare the constants.

This is needed for r500, since when indirect addressing is used,
it cannot reduce the amount of constants needed, and that it is
restricted to 256 constant slots.

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