usb: chipidea: add a flag for turn on vbus early for host

Some usb PHYs need power supply from vbus to make it work, eg mxs-phy, if
there is no vbus, USB PHY will not in correct state when the controller starts
to work, for host, this requires vbus should be turned on before setting port
power(PP) of ehci, to work with this kind of USB PHY design, this patch adds
a flag CI_HDRC_TURN_VBUS_EARLY_ON, can be checked by host driver to turn on
vbus while start host.

Signed-off-by: Li Jun <jun.li@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>