of: property: Don't add links to absent suppliers

If driver core marks a firmware node as not a device, don't add fwnode
links where it's a supplier.

Fixes: e5904747 ("driver core: Set fw_devlink=on by default")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20210205222644.2357303-3-saravanak@google.com


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