UPSTREAM: usb: dwc3: gadget: move % operation to increment helpers

UPSTREAM: usb: dwc3: gadget: move % operation to increment helpers

By moving our % DWC3_NUM_TRB operation to the
increment helpers, the rest of the driver can be
simplified.

It's also a good practice to make sure we will have
a single place dealing with details about how to
increment our enqueue and dequeue pointers.

Change-Id: I4a218a52f6d7c8c2797c64772e25dc734fc6c861
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>
(cherry picked from commit 4faf75504a7db790483aa419d8f61e58cec4934c)