zink: always use NEAREST for zs blits
LINEAR is illegal, and swapping filtering at this point still seems to be conformant given questionable GL spec requirements for LINEAR zs filtering
cc: mesa-stable
https://gitlab.freedesktop.org/zmike/mesa/-/pipelines/803789
fixes https://gitlab.freedesktop.org/mesa/mesa/-/jobs/35744505
Edited by Mike Blumenkrantz