usb: core: need to call usb_phy_notify_connect after device setup

Since we notify disconnecting based on the usb device is existed
(port_dev->child, the child device at roothub is not NULL), we
need to notify connect after device has been registered.

This fixes a bug that do fast plug in/out test, and the notify_disconnect
is not called due to roothub child is NULL and the enumeration has failed.

Cc: v3.17+ <stable@vger.kernel.org>
Signed-off-by: Tony Zheng <Tony.Zheng@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>