phylib: add *_direct() variants of phy_connect and phy_attach functions

Add phy_connect_direct() and phy_attach_direct() functions so that
drivers can use a pointer to the phy_device instead of trying to determine
the phy's bus_id string.

This patch is useful for OF device tree descriptions of phy devices where
the driver doesn't need or know what the bus_id value in order to get a
phy_device pointer.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>