panfrost: Don't advertise AFBC mods when the format is not supported
On Bifrost, AFBC is not supported if the format has a non-identity swizzle. For internal resources we fix the format at runtime, but this fixup is not applicable when we export the resource. Don't advertise AFBC modifiers on such formats.
Signed-off-by: Boris Brezillon boris.brezillon@collabora.com