usb: dwc2: gadget: Remove call to dwc2_hsotg_init()

Remove call to dwc2_hsotg_init() from dwc2_gadget_init(). The
gadget_init function should not access any device registers because the
mode isn't guaranteed here.

Also, this is already called elsewhere before anything starts on the
gadget so it is not necessary here.

Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>