radv: Fix DCC compatible formats.

DCC was disabled when the image format is !!supported, which is one ! too many.

Ironically the commit that introduced it was supposed to lead to more DCC use ...

Fixes: 969537d9 "radv: Add support for more DCC compression with VK_KHR_image_format_list."
Reviewed-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit 70b5e85f)