net: sfp: split the PHY probe from sfp_sm_mod_init()

Move the PHY probe into a separate function, splitting it from
sfp_sm_mod_init().  This will allow us to eliminate the 50ms mdelay()
inside 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>