pan/midgard: Introduce invert field

This will enable us to fuse inverts in various ways. Marginal hurt:

total instructions in shared programs: 3610 -> 3611 (0.03%)
instructions in affected programs: 67 -> 68 (1.49%)
helped: 0
HURT: 1

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
5 files changed