i965: Drop unused STATE_TEXRECT_SCALE code.

i965: Drop unused STATE_TEXRECT_SCALE code.

In the past, we used this on Gen4-5 to transform non-normalized texture
coordinates (for sampler2DRect) to normalized ones.  We also used it on
Gen6-7.5 for sampler2DRect with GL_CLAMP.

Jason dropped this code in 6c8ba59cff14a1a86273f4008ff2a8e68335ab25
in favor of using nir_lower_tex(), which just does a textureSize()
call.  But we were still setting up these state references for
useless uniform data.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chris Forbes <chrisforbes@google.com>