net: phylink: avoid resolving link state too early

During testing on Armada 388 platforms, it was found with a certain
module configuration that it was possible to trigger a kernel oops
during the module load process, caused by the phylink resolver being
triggered for a currently disabled interface.

This problem was introduced by changing the way the SFP registration
works, which now can result in the sfp link down notification being
called during phylink_create().

Fixes: b5bfc21a

 ("net: sfp: do not probe SFP module before we're attached")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>