i965: Remove base miplevel from sampler state.

i965: Remove base miplevel from sampler state.

Gen9 changes the meaning of this to coarse LOD quality mode. Although that's a
desirable thing to be setting, it doesn't match the gen8 behavior and this was
unintentional. More importantly, we don't ever use this field. So instead of
getting it "wrong" drop it entirely.

This is a respin of a patch which only [incorrectly] tried to address gen9.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>