nv20: Fix GL_CLAMP

nv20: Fix GL_CLAMP

v2: Force T and R wrap modes to GL_CLAMP_TO_EDGE for 1D textures.
This fixes a regression in tex1d-2dborder.  The test uses a 1D texture
but it provides S and T texture coordinates.  Since the T wrap mode
would (correctly) be set to GL_CLAMP, the texture would gradually
blend (incorrectly) with the border color.

I also tried setting NV20_3D_TEX_FORMAT_DIMS_1D instead of
NV20_3D_TEX_FORMAT_DIMS_2D for 1D textures, but that did not help.

It is possible that the same problem exists for 2D textures with the
R-wrap mode, but I don't think there are any piglit tests for that.

No test changes on NV20 (10de:0201).

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>