net: phy: provide and use genphy_read_status_fixed()

There are two drivers and generic code which contain exactly the same
code to read the status of a PHY operating without autonegotiation
enabled. Rather than duplicate this code, provide a helper to read
this information.

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