usb: pch_udc: usb gadget device support for Intel Quark X1000

This patch is to enable the USB gadget device for Intel Quark X1000

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@intel.com>
Signed-off-by: Bing Niu <bing.niu@intel.com>
Signed-off-by: Alvin (Weike) Chen <alvin.chen@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>