driver core: Have fw_devlink use DL_FLAG_INFERRED

This will be useful in identifying device links created only due to
fw_devlink when we need to break cyclic dependencies due to fw_devlink.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20201218031703.3053753-4-saravanak@google.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>