usb: dwc2: gadget: fix enumeration issues

Excessive debug messages might cause timing issues that prevent correct
usb enumeration. This patch hides information about USB bus reset to let
driver enumerate fast enough to avoid making host angry. This fixes
endless enumeration and usb reset loop observed with some Linux hosts.

Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>