usb: dwc2: Postponed gadget registration to the udc class driver

usb: dwc2: Postponed gadget registration to the udc class driver

commit 207324a321a866401b098cadf19e4a2dd6584622 upstream.

During dwc2 driver probe, after gadget registration to the udc class
driver, if exist any builtin function driver it immediately bound to
dwc2 and after init host side (dwc2_hcd_init()) stucked in host mode.
Patch postpone gadget registration after host side initialization done.

Fixes: 117777b2c3bb9 ("usb: dwc2: Move gadget probe function into platform code")
Reported-by: kbuild test robot <lkp@intel.com>
Tested-by: Marek Vasut <marex@denx.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Minas Harutyunyan <hminas@synopsys.com>
Link: https://lore.kernel.org/r/f21cb38fecc72a230b86155d94c7e60c9cb66f58.1591690938.git.hminas@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>