Move DWC2 driver out of staging

The DWC2 driver should now be in good enough shape to move out of
staging. I have stress tested it overnight on RPI running mass
storage and Ethernet transfers in parallel, and for several days
on our proprietary PCI-based platform.

Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --cc MAINTAINERS
Simple merge

diff --cc drivers/staging/Kconfig
Simple merge

diff --cc drivers/staging/Makefile
Simple merge

diff --cc drivers/staging/dwc2/TODO
Simple merge

diff --cc drivers/usb/Kconfig
Simple merge

diff --cc drivers/usb/Makefile
Simple merge

diff --cc drivers/usb/dwc2/Kconfig
Simple merge

diff --cc drivers/usb/dwc2/Makefile
Simple merge

diff --cc drivers/usb/dwc2/core.c
Simple merge

diff --cc drivers/usb/dwc2/core.h
Simple merge

diff --cc drivers/usb/dwc2/core_intr.c
Simple merge

diff --cc drivers/usb/dwc2/hcd.c
Simple merge

diff --cc drivers/usb/dwc2/hcd.h
Simple merge

diff --cc drivers/usb/dwc2/hcd_ddma.c
Simple merge

diff --cc drivers/usb/dwc2/hcd_intr.c
Simple merge

diff --cc drivers/usb/dwc2/hcd_queue.c
Simple merge

diff --cc drivers/usb/dwc2/hw.h
Simple merge

diff --cc drivers/usb/dwc2/pci.c
Simple merge

diff --cc drivers/usb/dwc2/platform.c
Simple merge