net: phy: marvell: unlock after phy_select_page() failure

We need to call phy_restore_page() even if phy_select_page() fails.
Otherwise we are holding the phy_lock_mdio_bus() lock.  This requirement
is documented at the start of the phy_select_page() function.

Fixes: a618e86d

 ("net : phy: marvell: Speedup TDR data retrieval by only changing page once")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>