nv50/ir: always emit the NDV bit for OP_QUADOP

nv50/ir: always emit the NDV bit for OP_QUADOP

This silences a divergent error found with F1 2015.

Basically, the NDV bit has to be set when a FSWZ instruction is
inside divergent code, but it's not needed otherwise. The correct
fix should be to set it only in divergent code situations.

GM107 emitter already sets that bit.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: <mesa-stable@lists.freedesktop.org>