net: phy: remove phy_error from phy_disable_interrupts

All callers of phy_disable_interrupts() call phy_error() in the error
case. Therefore we don't need to do this within the function too.
This change also allows us to use phy_disable_interrupts() in code
holding phydev->lock (because phy_error() can take this lock).

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>