phy: usb: Add support for wake and USB low power mode for 7211 S2/S5

Add support for 7211 USB wake. Disable all possible 7211 USB logic
for S2/S5 if USB wake is not enabled.

On the 7211, the XHCI wake signal was not connected properly and
only goes to the USB1_USB1_CTRL_TP_DIAG1 diagonstic register.
The workaround is to have VPU code running that polls for the
proper bit in the DIAG register and to wake the system when
the bit is asserted.

Signed-off-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>