usb: gadget: fsl: Introduce FSL_USB2_PHY_UTMI_DUAL for usb gadget

Introduce FSL_USB2_PHY_UTMI_DUAL in gadget driver for setting
phy in SOCs with utmi dual phy

Acked-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Nikhil Badola <nikhil.badola@freescale.com>
Tested-by: Tiago Brusamarello <tbrusa@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>