intel/fs: Respect CHV/BXT regioning restrictions in copy propagation pass.

intel/fs: Respect CHV/BXT regioning restrictions in copy propagation pass.

Currently the visitor attempts to enforce the regioning restrictions
that apply to double-precision instructions on CHV/BXT at NIR-to-i965
translation time.  It is possible though for the copy propagation pass
to violate this restriction if a strided move is propagated into one
of the affected instructions.  I've only reproduced this issue on a
future platform but it could affect CHV/BXT too under the right
conditions.

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>