mesa: Prefer non-swizzled formats for most sized internalformats

mesa: Prefer non-swizzled formats for most sized internalformats

These formats can be cast to others (with different component types or
sizes) via ARB_texture_view or ARB_shader_image_load_store. We want
them to be laid out consistently so that we can just reinterpret the
memory with a different format.

In V1, this was done conditionally on a 'prefer_no_swizzle' flag which
was set in TexStorage/TextureView paths, but we need the same behavior
for ARB_shader_image_load_store (which also works with images created
via TexImage, so we don't want it to be conditional.

Signed-off-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Acked-by: Eric Anholt <eric@anholt.net>