T4/usb: move usb 2.0 utmi dual phy init code to cpu_init.c

This is what we have done for the UTMI PHY on P3041/P5020. Then the PHY
initialization can be reused in kernel without  “usb start” command.

Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>