usb: dwc3: gadget: Wrap around when skip TRBs

When skipping TRBs, we need to account for wrapping around the ring
buffer and not modifying some invalid TRBs. Without this fix, dwc3 won't
be able to check for available TRBs.

Change-Id: I67d1deb78f5ecf03c50c4b2c40a7a067c7efa659
Cc: stable <stable@vger.kernel.org>
Fixes: 7746a8df ("usb: dwc3: gadget: extract dwc3_gadget_ep_skip_trbs()")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Git-commit: 2dedea035ae82c5af0595637a6eda4655532b21e
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Mayank Rana <mrana@codeaurora.org>