usb: dwc3: gadget: Look ahead when setting IOC

Previously if we run out of TRBs for the last SG entry that requires
an extra TRB, we set interrupt-on-completion (IOC) bit to an already
prepared TRB (i.e. HWO=1). This logic is not clean, and it's not a
typical way to prepare TRB. Also, this prevents showing IOC setup in
tracepoint when __dwc3_prepare_one_trb() is executed. Instead, let's
look ahead when preparing TRB to know whether to set the IOC bit before
the last SG entry. This requires adding a new parameter "must_interrupt"
to dwc3_prepare_one_trb().

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>