ANDROID: misc: hisi_hikey_usb: Driver to support usb functionality of Hikey960

The HiKey960 has a fairly complex USB configuration due to it
needing to support a USB-C port for host/device mode and multiple
USB-A ports in host mode using a single USB controller.

See schematics here:
  https://github.com/96boards/documentation/raw/master/consumer/hikey/hikey960/hardware-docs/HiKey960_Schematics.pdf

This driver acts as a usb-role-switch intermediary, intercepting
the role switch notifications from the tcpm code, and passing
them on to the dwc3 core.

In doing so, it also controls the onboard hub and power gpios in
order to properly route the data lines between the USB-C port
and the onboard hub to the USB-A ports.

NOTE: It was noted that controlling the TYPEC_VBUS_POWER_OFF and
TYPEC_VBUS_POWER_ON values here is not reccomended. I'm looking
for a way to remove that bit from the logic here, but wanted to
still get feedback on this approach.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
CC: ShuFan Lee <shufan_lee@richtek.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Chunfeng Yun <chunfeng.yun@mediatek.com>
Cc: Yu Chen <chenyu56@huawei.com>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jun Li <lijun.kernel@gmail.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jack Pham <jackp@codeaurora.org>
Cc: linux-usb@vger.kernel.org
Cc: devicetree@vger.kernel.org
Bug: 146450171
Link: https://lore.kernel.org/lkml/20191212014233.32799-9-john.stultz@linaro.org/


Signed-off-by: Yu Chen <chenyu56@huawei.com>
[jstultz: Major rework to make the driver a usb-role-switch
          intermediary]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: Icf381520abd46d083750d01f91e478321560fbf9