i965: Add support for correct GL_CLAMP behavior by clamping coordinates.

This removes the stupid strict-conformance fallback code I broke when
adding ARB_sampler_objects.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36572
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> (v1)
9 files changed