net: sfp: move sfp_register_socket call from sfp_remove to sfp_probe

Commit c4ba68b8 backported from upstream to 4.14 stable was
probably applied wrongly, and instead of calling sfp_register_socket in
sfp_probe, the socket registering code was put into sfp_remove. This is
obviously wrong.

The commit first appeared in 4.14.104. Fix it for the next 4.14 release.

Fixes: c4ba68b8 ("net: sfp: do not probe SFP module before we're attached")
Cc: stable <stable@vger.kernel.org>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>