usb: gadget: MBIM: Add support for MBIM over DWC3 controller

MBIM is a USB tethering interface that is using HW accelerated
path via BAM2BAM.
This change adds the required support to enable the BAM2BAM
path for ECM also on DWC3 new USB controller.

Change-Id: If1acd120597d79a57057db5e22bdf0a09e60e98c
Signed-off-by: Bar Weiner <bweiner@codeaurora.org>
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>