usb: dwc3: dbm: fix ep reset based on usb ep num

Making the proper distinction between ep_reset function
calls that are made from within the dbm driver (in which
case the dbm ep number is provided) vs. when the call
is made from the dwc3 driver (in which case the usb ep
number is provided).

Change-Id: I0950a324da44c8abe780ad0a7b1095143a294a0b
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>
Signed-off-by: Bar Weiner <bweiner@codeaurora.org>