fb: Reduce priority of resource conflict message

It's expected that efifb will conflict with a native driver, so the
handover message should be informational rather than an error.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>