usb: dwc3: Add workaround for ISOC packet drop issue

DWC3 Revisions <= 2.50a have an issue which can result in dropping
of ISOC packets.
Due to this problem, we might experience a glitch in the associated
audio or video application. The workaround is to disable DCTL[10:9]
when an ISOC transfer is in progress.

Change-Id: Ida73d08a1649ae4e6d838f325c36c9002bf03854
Signed-off-by: Amit Blay <ablay@codeaurora.org>
Signed-off-by: Nadine Toledano <nadinet@codeaurora.org>
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>