net: sfp: handle module remove outside state machine

Removing a module resets the module state machine back to its initial
state.  Rather than explicitly handling this in every state, handle it
early on outside of the state machine.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>