usb: penwell_otg: Add Intel Penwell USB OTG Transceiver driver

usb: penwell_otg: Add Intel Penwell USB OTG Transceiver driver

Description
  This driver tries to implement host/device role switch according to
  OTG 2.0 spec on MFLD. The actual host and device functions are
  accomplished in modified EHCI driver and Intel Penwell USB OTG device
  controller driver. This is the first version and it only support Host
  Peripheral role switch per different USB cable. Development work is
  still on going, more features will be submitted soon after verified.

Dependency
  CONFIG_INTEL_SCU_IPC - IPC driver.

Enable driver in Kernel
  "Device Drivers"  --->  "USB support"  --->
          "Intel Penwell USB OTG dual-role support"

Kernel configs
  CONFIG_INTEL_SCU_IPC=y
  CONFIG_USB=y
  CONFIG_USB_OTG=y
  CONFIG_USB_OTG_UTILS=y
  CONFIG_PENWELL_OTG=y

Todo List
  USB Charging Support
  Power management (runtime)
  MHL-USB coexistence
  HNP/HNP Polling/SRP
  ADP(Attach Detection Protocol) Support

Change-Id: Ie9daf11fc21f03be659ed6c8992a4ac904421e0f
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>