UPSTREAM: usb: dwc3: fix for the isoc transfer EP_BUSY flag

UPSTREAM: usb: dwc3: fix for the isoc transfer EP_BUSY flag

commit f3af36511e60 ("usb: dwc3: gadget: always
enable IOC on bulk/interrupt transfers") ended up
regressing Isochronous endpoints by clearing
DWC3_EP_BUSY flag too early, which resulted in
choppy audio playback over USB.

Fix that by partially reverting original commit and
making sure that we check for isochronous endpoints.

Change-Id: If2b5897f005bc5f6a4f475e8371c2654ac04a44a
Fixes: f3af36511e60 ("usb: dwc3: gadget: always enable IOC
		on bulk/interrupt transfers")
Cc: <stable@vger.kernel.org>
Signed-off-by: Konrad Leszczynski <konrad.leszczynski@intel.com>
Signed-off-by: Rafal Redzimski <rafal.f.redzimski@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>
(cherry picked from commit 9cad39fe4e4a4fe95d8ea5a7b0692b0a6e89e38b)