ANDROID: usb: dwc3: export tracepoint for dwc3 read/write

There are two tracepoints in dwc3_readl() and dwc3_writel().
This patch will export the tracepoints so that vendor modules
can use them.

Bug: 184920962
Signed-off-by: Ray Chi <raychi@google.com>
Change-Id: I1170d853be1fa1c47afbba133567b1996418d8e8