glsl: Pack integer and double varyings as flat even if interpolation mode is none
v2: Also update varying_matches::compute_packing_class(). Suggested by
Timothy Arceri.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96358
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: "12.0" <mesa-stable@lists.freedesktop.org>
Cc: Gregory Hainaut <gregory.hainaut@gmail.com>
Cc: Ilia Mirkin <imirkin@alum.mit.edu>
(cherry picked from commit
3119871bd9558e5881466b70a4c366d2f83bba82)