dwc3: gadget: Add support for no interrupt flag for sg reqs

Currently controller driver does not honor the no interrupt
flag from function driver and always sets LST (xfer complete) bit
on last request. High throughput functions like rndis/rmnet can
queue multiple requests and in some scenario endup with large
number requests pending with h/w. They will only be recycled after
hw completes the last request. Add support for no interrupt flag
flag for sg (scatter/gather) requests so that application driver
can decide when to generate interrupt. Controller will generate
xfer-in-progress event when ioc is set.

Change-Id: If02eb8602cafdbabf4bbe7f829711e9aaa304035
Signed-off-by: Vamsi Krishna <vskrishn@codeaurora.org>