usb: dwc3: gadget: fix trb ring full bug

usb: dwc3: gadget: fix trb ring full bug

The upstream commit 5e8ec28765 (usb: dwc3: gadget: Handle TRB
index 0 when full or empty) only use the HWO = 1 to check if
the TRB ring is full. But refer to DWC3 databook Version 3.00a,
8.2.3.2 TRB Control Bit Rules: When an OUT endpoint receives a
short packet, some TRBs in a chain may still have their HWO bit
set to 1 while belonging to software.

So if HWO=1 and CSP=1 on OUT endpoint, it also means that TRB
ring is empty, software may reclaim those TRBs even though HWO=1.

TEST=use MTP to transfer big data, and then cancel the transition，
check if it can transfer again.

Change-Id: I45cc683dc733ff7a642cfcd3ebc20455ef677753
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>