net: phy: broadcom: Allow BCM54810 to use bcm54xx_adjust_rxrefclk()

The function bcm54xx_adjust_rxrefclk() works correctly on the BCM54810
PHY, allow this device ID to proceed through.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>