phy: let phy_provider_register be the last step in registering PHY

Registering phy_provider before creating the PHY can result in PHY
callbacks being invoked which will lead to aborts. In order to avoid this
invoke phy_provider_register after phy_create and phy_set_drvdata.

Reported-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>