usb: gadget: Disable transfer-complete interrupt on BAM2BAM transfers

Enabling the transfer-complete interrupt on BAM2BAM transfer
is not required and can cause watch-dog bark on high throughput.

Change-Id: I7d80c7ff0e29b5087fb337020e9cd7e52488c767
Signed-off-by: Bar Weiner <bweiner@codeaurora.org>