i965/vec4: Drop writemasks on scratch reads.

This code is complete nonsense and has apparently existed since I first
implemented register spilling in the VS two years ago.

Scratch reads are SEND messages, which ignore the destination writemask.

The comment about "data that may not have been written to scratch" is
also confusing - we always spill whole 4x2 registers, so such data
simply does not exist.  We can safely ignore the writemask.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
freedreno: helper to calc layer/level offset

Rather than duplicating this everywhere.  Especially as on a4xx the
layout of layers and levels differs based on texture type.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
freedreno: add is_a3xx()/is_a4xx() helpers

A bunch of open-coded 'gpu_id > 300's seems like it will eventually
cause problems with future generations.  There were already a few minor
problems with caps for features that still need additional work on a4xx.

Signed-off-by: Rob Clark <robclark@freedesktop.org>
freedreno: update generated headers

Signed-off-by: Rob Clark <robclark@freedesktop.org>
freedreno/a4xx: mipmaps

Signed-off-by: Rob Clark <robclark@freedesktop.org>