Walking the format/modifier list to try to find out if our FB is
compatible with the plane is surprisingly expensive. Since the plane's
capabilities are static over the lifetime of the KMS device, cache the
set of planes for which the FB is theoretically
format/modifier-compatible when it's created, and use that to do an
early cull of the set of acceptable planes.

Signed-off-by: Daniel Stone <daniels@collabora.com>