st/mesa: overhaul vertex/fragment sampler and sampler views.

st/mesa: overhaul vertex/fragment sampler and sampler views.

This fixes piglits fragment-and-vertex-texturing test on llvmpipe for me.

I've no idea if someone had another plan for this that is smarter than what
I've done here, but what I've basically done is

split fragment and vertex sampler and sampler_view setup function, factor
out the common chunks of both.

side-cleanups:
drop st->state.sampler_list - unused
don't update border color if we have no border color.

should fix https://bugs.freedesktop.org/show_bug.cgi?id=35849

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Brian Paul <brianp@vmware.com>