intel/fs: Relax type matching rules in cmod propagation from MOV instructions

intel/fs: Relax type matching rules in cmod propagation from MOV instructions

To allow cmod propagation from a MOV in a sequence like:

    and(16)         g31<1>UD       g20<8,8,1>UD   g22<8,8,1>UD
    mov.nz.f0(16)   null<1>F       g31<8,8,1>D

A similar change to the vec4 backend had no effect.

Somewhere between c1ec5820593 and 40fc4b5acd6 (1,094 commits) the
effectiveness of this patch diminished, and as of commit d7e0d47b9de
(nir: Add a bunch of b2[if] optimizations) this optimization no longer
has any effect on any platform.

A later patch "intel/fs: Use De Morgan's laws to avoid logical-not of a
logic result on Gen8+," generates some instruction sequences that
require this change in order for cmod propagation to make progress.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>