nir: fix typo in idiv lowering, causing large-udiv-udiv failures

nir: fix typo in idiv lowering, causing large-udiv-udiv failures

In nv50, and in the python script that Rob circulated, we do:

   bld.mkCmp(OP_SET, CC_GE, TYPE_U32, (s = bld.getSSA()), TYPE_U32, m, b);

Do the same in the nir div lowering pass. This fixes the large-udiv-udiv
piglit tests on freedreno.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Rob Clark <robclark@freedesktop.org>