i965: Consistently use nr_pull_params instead of NumParameters.

i965: Consistently use nr_pull_params instead of NumParameters.

NumParameters used to be an upper bound on the number of vec4s to be
uploaded, which was basically safe (unless your buffer was bound near
the top of address space *and* you array indexed outside the buffer, in
which case I think you might GPU hang).  As I migrate the driver away
from ParameterValues[], this is no longer true.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>