net: phy: use phy_resolve_aneg_pause()

Several drivers code their own version of this, working from the LPA
register, after setting the ethtool link partner advertisement bitmask.
Use the generic function instead.

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>