nvc0/ir: reset the base offset for indirect images accesses
In presence of an indirect image access, the base offset should be zeroed because the stride will be computed twice. This is a pretty rare situation but it can happen when tex.r > 0. Signed-off-by:Samuel Pitoiset <samuel.pitoiset@gmail.com> Reviewed-by:
Ilia Mirkin <imirkin@alum.mit.edu> Cc: "11.2 12.0" <mesa-stable@lists.freedesktop.org> (cherry picked from commit f3b9fff3)